1 | .\" AWK Reference Card --- Arnold Robbins, arnold@skeeve.com
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2 | .\"
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3 | .\" Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002,
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4 | .\" 2003, 2004, 2005 Free Software Foundation, Inc.
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5 | .\"
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6 | .\" Permission is granted to make and distribute verbatim copies of
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7 | .\" this reference card provided the copyright notice and this permission
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8 | .\" notice are preserved on all copies.
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9 | .\"
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10 | .\" Permission is granted to process this file through troff and print the
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11 | .\" results, provided the printed document carries copying permission
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12 | .\" notice identical to this one except for the removal of this paragraph
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13 | .\" (this paragraph not being relevant to the printed reference card).
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14 | .\"
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15 | .\" Permission is granted to copy and distribute modified versions of this
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16 | .\" reference card under the conditions for verbatim copying, provided that
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17 | .\" the entire resulting derived work is distributed under the terms of a
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18 | .\" permission notice identical to this one.
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19 | .\"
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20 | .\" Permission is granted to copy and distribute translations of this
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21 | .\" reference card into another language, under the above conditions for
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22 | .\" modified versions, except that this permission notice may be stated in
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23 | .\" a translation approved by the Foundation.
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24 | .\"
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25 | .\" Strings to save typing
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26 | .ds AK \*(FCawk\*(FR
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27 | .ds GK \*(FCgawk\*(FR
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28 | .ds PK \*(FCpgawk\*(FR
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29 | .ds NK Bell Labs \*(FCawk\*(FR
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30 | .ds MK \*(FCmawk\*(FR
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31 | .\"
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32 | .\"
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33 | .de TD\" tab defaults
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34 | .ta .2i .78i 1i 1.2i 1.4i 1.7i
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35 | ..
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36 | .de TE
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37 | .TD
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38 | ..
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39 |
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40 | .sp
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41 | .ce
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42 | \*(CD\f(HB\s+8AWK REFERENCE\s0\*(FR
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43 | .sp
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44 | .\" --- Table Of Contents
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45 | .ta 2.4i 2.6iR
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46 | .lc .
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47 | .ES
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48 | .in +.2i
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49 | .nf
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50 | \*(FRAction Statements 7
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51 | Arrays 11
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52 | Awk Program Execution 4
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53 | Bit Manipulation Functions (\*(GK) 16
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54 | Bug Reports 2
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55 | Closing Redirections 12
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56 | Command Line Arguments (standard) 2
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57 | Command Line Arguments (\*(GK) 3
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58 | Command Line Arguments (\*(MK) 4
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59 | Conversions And Comparisons 9
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60 | Copying Permissions 18
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61 | Definitions 2
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62 | Dynamic Extensions (\*(GK) 14
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63 | Environment Variables (\*(GK) 16
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64 | Escape Sequences 8
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65 | Expressions 11
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66 | Fields 6
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67 | FTP/HTTP Information 18
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68 | Historical Features (\*(GK) 10
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69 | Input Control 12
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70 | Internationalization (\*(GK) 18
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71 | Lines And Statements 5
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72 | Localization (\*(GK) 17
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73 | Numeric Functions 14
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74 | Output Control 12
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75 | Pattern Elements 7
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76 | POSIX Character Classes (\*(GK) 6
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77 | Printf Formats 13
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78 | Records 6
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79 | Regular Expressions 5
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80 | Signals (\*(PK) 4
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81 | Special Filenames 14
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82 | String Functions 15
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83 | Time Functions (\*(GK) 16
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84 | User-defined Functions 17
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85 | Variables 8\*(CX
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86 | .in -.2i
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87 | .EB "\s+2\f(HBCONTENTS\*(FR\s0"
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88 | .sp .4
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89 | .TD
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90 | .fi
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91 | \*(CD\*(FRArnold Robbins wrote this reference card.
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92 | We thank
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93 | Brian Kernighan and Michael Brennan who reviewed it.
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94 | .sp .4
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95 | .SL
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96 | .sp .4
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97 | .so SRCDIR/ad.block
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98 | .\" a subtlety here; this line changes color. We rely on it
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99 | .\" also to provide a blank line.
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100 | \*(CD
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101 | .SL
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102 | .nf
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103 | \*(FRCopyright \(co 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
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104 | Free Software Foundation, Inc.
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105 | .nf
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106 | .BT
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107 |
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108 |
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109 | .\"
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110 | .\"
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111 | .\" --- Definitions
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112 | .fi
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113 | .ES
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114 | \*(CDThis card describes POSIX AWK, as well as the three
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115 | freely available \*(AK implementations
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116 | (see \fHFTP/HTTP Information\fP below).
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117 | \*(CLCommon extensions (in two or more versions) are printed in light blue.
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118 | \*(CBFeatures specific to just one version\(emusually GNU AWK (\*(GK)\(emare
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119 | printed in dark blue.
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120 | \*(CRExceptions and deprecated features are printed in red.
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121 | \*(CDFeatures mandated by POSIX are printed in black.
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122 | .sp .5
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123 | Several type faces are used to clarify the meaning:
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124 | .br
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125 | .nr IN \w'\(bu '
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126 | \(bu \*(FC\*(CN\fP is used for computer input.
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127 | .br
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128 | .fi
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129 | .in +\n(INu
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130 | .ti -\n(INu
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131 | \(bu\|\^\*(FI\*(IN\fP is used for emphasis, to indicate user input and for syntactic
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132 | placeholders, such as \*(FIvariable\fP or \*(FIaction\fP.
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133 | .in -\n(INu
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134 | .br
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135 | \(bu \*(RN is used for explanatory text.
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136 | .sp .5
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137 | \*(FInumber\fP \- a floating point number as in ANSI C, such as
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138 | \*(FC3\*(FR,
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139 | \*(FC2.3\*(FR,
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140 | \*(FC.4\*(FR,
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141 | \*(FC1.4e2\*(FR
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142 | or
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143 | \*(FC4.1E5\*(FR.
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144 | \*(CBNumbers may also be given in octal or hexadecimal: e.g.,
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145 | \*(FC011\*(FR or \*(FC0x11\*(FR.\*(CD
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146 | .sp .5
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147 | \*(FIescape sequences\fP \- a special sequence of characters beginning
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148 | with a backslash, used to describe otherwise unprintable characters.
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149 | (See \fHEscape Sequences\fP below.)
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150 | .sp .5
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151 | \*(FIstring\fP \- a group of characters enclosed in double quotes.
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152 | Strings may contain \*(FIescape sequences\*(FR.
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153 | .sp .5
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154 | \*(FIregexp\fP \- a regular expression, either a regexp constant
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155 | enclosed in forward slashes, or a dynamic regexp computed at run-time.
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156 | Regexp constants may contain \*(FIescape sequences\*(FR.
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157 | .sp .5
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158 | \*(FIname\fP \- a variable, array or function name.
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159 | .sp .5
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160 | \*(FIentry\fP(\*(FIN\fP) \- entry \*(FIentry\fP in section \*(FIN\fP of the
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161 | UNIX reference manual.
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162 | .sp .5
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163 | \*(FIpattern\fP \- an expression describing an input record to be matched.
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164 | .sp .5
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165 | \*(FIaction\fP \- statements to execute when an input record is matched.
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166 | .sp .5
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167 | \*(FIrule\fP \- a pattern-action pair, where the pattern or action may
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168 | be missing.\*(CX
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169 | .EB "\s+2\f(HBDEFINITIONS\*(FR\s0"
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170 |
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171 | .\"
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172 | .\"
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173 | .\" --- Command Line Arguments
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174 | .ES
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175 | .fi
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176 | \*(CDCommand line arguments control setting the field separator,
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177 | setting variables before the \*(FCBEGIN\fP rule is run, and
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178 | the location of AWK program source code.
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179 | Implementation-specific command line arguments change
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180 | the behavior of the running interpreter.
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181 | .sp .5
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182 | .TS
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183 | expand;
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184 | l lw(2.2i).
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185 | \*(FC\-F \*(FIfs\*(FR use \*(FIfs\fP for the input field separator.
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186 | \*(FC\-v\*(FI var\*(FC\^=\^\*(FIval\*(FR T{
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187 | assign the value \*(FIval\*(FR to the variable \*(FIvar\*(FR
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188 | before execution of the program begins. Such
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189 | variable values are available to the \*(FCBEGIN\fP rule.
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190 | T}
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191 | \*(FC\-f \*(FIprog-file\*(FR T{
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192 | read the AWK program source from the file
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193 | \*(FIprog-file\*(FR, instead of from the first command
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194 | line argument. Multiple \*(FC\-f\*(FR options may be used.
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195 | T}
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196 | \*(FC\-\^\-\*(FR signal the end of options.
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197 | .TE
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198 | .sp .5
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199 | .fi
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200 | \*(CLThe following options are accepted by both \*(NK and \*(GK
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201 | \*(CR(ignored by \*(GK, not in \*(MK).\*(CL
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202 | .sp .5
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203 | .nf
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204 | .TS
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205 | expand, tab(%);
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206 | l lw(2.2i).
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207 | \*(FC\-mf \*(FIval\*(FR%set the maximum number of fields to \*(FIval\fP
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208 | \*(FC\-mr \*(FIval\*(FR%set the maximum record size to \*(FIval\fP\*(CX
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209 | .TE
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210 | .EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (standard)\*(FR\s0"
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211 |
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212 | .\" --- Bug Reports
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213 | .ES
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214 | .fi
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215 | \*(CDIf you find a bug in this reference card, please report it via electronic
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216 | mail to \*(FCbug-gawk@gnu.org\*(FR.\*(CX
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217 | .EB "\s+2\f(HBBUG REPORTS\*(FR\s0"
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218 |
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219 | .BT
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220 |
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221 | .\"
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222 | .\"
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223 | .\" --- Command Line Arguments (gawk)
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224 | .ES
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225 | .fi
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226 | \*(CDThe following options are specific to \*(GK.
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227 | You may also use ``\*(FC\-W \*(FIoption\*(FR''
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228 | for full POSIX compliance.
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229 | Long options may abbreviated as long as the abbreviation
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230 | remains unique.
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231 | .sp .5
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232 | .ig
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233 | .\" This option is left undocumented, on purpose.
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234 | \*(FC\-\^\-nostalgia\*(FR%T{
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235 | provide a moment of nostalgia for
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236 | long time \*(AK users.
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237 | T}
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238 | ..
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239 | .TS
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240 | expand, tab(%);
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241 | l lw(1.3i).
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242 | \*(FC\-\^\-assign \*(FIvar\*(FC\^=\^\*(FIval\*(FR%just like \*(FC\-v\fP.
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243 | \*(FC\-\^\-field-separator \*(FIfs\*(FR%just like \*(FC\-F\fP.
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244 | \*(FC\-\^\-file \*(FIprog-file%\*(FRjust like \*(FC\-f\fP.
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245 | .TE
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246 | .TS
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247 | expand, tab(%);
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248 | ls
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249 | l lw(2.2i).
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250 | \*(FC\-\^\-compat\*(FR, \*(FC\-\^\-traditional\*(FR
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251 | %T{
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252 | disable \*(GK-specific extensions
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253 | (the use of \*(FC\-\^\-traditional\*(FR is preferred).
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254 | T}
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255 | .T&
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256 | ls
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257 | l lw(2.2i).
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258 | \*(FC\-\^\-copyleft\*(FR, \*(FC\-\^\-copyright\*(FR
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259 | %T{
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260 | print the short version of the GNU
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261 | copyright information on \*(FCstdout\*(FR.
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262 | T}
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263 | .T&
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264 | ls
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265 | l lw(2.2i).
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266 | \*(FC\-\^\-dump-variables\*(FR[\*(FC=\*(FIfile\*(FR]
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267 | %T{
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268 | print a sorted list of global variables,
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269 | their types and final values to
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270 | \*(FIfile\*(FR.
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271 | If no \*(FIfile\*(FR
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272 | is provided, \*(FCgawk\*(FR
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273 | uses \*(FCawkvars.out\*(FR.
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274 | T}
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275 | \*(FC\-\^\-exec \*(FIfile\*(FR%T{
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276 | read program text from \*(FIfile\fP. No other
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277 | options are processed. Useful with \*(FC#!\fP.
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278 | Also disables command-line variable assignments.
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279 | T}
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280 | \*(FC\-\^\-gen\-po\*(FR%T{
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281 | process the program and print a GNU \*(FCgettext\*(FR
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282 | format \*(FC\&.po\*(FR format file on standard output,
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283 | containing the text of all strings that were marked
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284 | for localization.
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285 | T}
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286 | .T&
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287 | ls
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288 | l lw(2.2i).
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289 | \*(FC\-\^\-help\*(FR, \*(FC\-\^\-usage\*(FR
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290 | %T{
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291 | print a short summary of the available
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292 | options on \*(FCstdout\*(FR, then exit zero.
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293 | T}
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294 | .T&
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295 | ls
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296 | l lw(2.2i).
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297 | \*(FC\-\^\-lint\*(FR[\*(FC=\*(FIvalue\*(FR]
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298 | %T{
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299 | warn about constructs that are dubious
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300 | or non-portable to other \*(AKs.
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301 | With an optional argument of \*(FCfatal\*(FR,
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302 | lint warnings become fatal errors.
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303 | With an optional argument of
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304 | \*(FCinvalid\*(FR,
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305 | only warnings about things that are
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306 | actually invalid are issued. (This is not fully implemented yet.)
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307 | T}
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308 | .T&
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309 | l lw(2.2i).
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310 | \*(FC\-\^\-lint\-old\*(FR%T{
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311 | warn about constructs that are not
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312 | portable to the original version of
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313 | Unix \*(AK.
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314 | T}
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315 | .T&
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316 | ls
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317 | l lw(2.2i).
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318 | \*(FC\-\^\-non\-decimal\-data\*(FR
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319 | %T{
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320 | recognize octal and hexadecimal values in input data.
|
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321 | \*(FIUse this option with great caution!\*(FR
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322 | T}
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323 | .T&
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324 | l lw(2.2i).
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325 | \*(FC\-\^\-posix\*(FR%T{
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326 | disable common and GNU extensions.
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327 | Enable \*(FIinterval expressions\*(FR in regular
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328 | expression matching (see \fHRegular
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329 | Expressions\fP below).
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330 | T}
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331 | .T&
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332 | ls
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333 | l lw(2.2i).
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334 | \*(FC\-\^\-profile\*(FR[\*(FC=\*(FIprof_file\*(FR]
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335 | %T{
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336 | send profiling data to \*(FIprof_file\*(FR
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337 | (default: \*(FCawkprof.out\*(FR).
|
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338 | With \*(GK,
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339 | the profile is just a ``pretty printed'' version of the program.
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340 | With \*(PK,
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341 | the profile contains execution counts in the left margin
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342 | of each statement in the program.
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343 | T}
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344 | .T&
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345 | ls
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346 | l lw(2.2i).
|
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347 | \*(FC\-\^\-re\-interval\*(FR
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348 | %T{
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349 | enable \*(FIinterval expressions\*(FR in regular
|
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350 | expression matching (see \fHRegular
|
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351 | Expressions\fP below). Useful if
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352 | \*(FC\-\^\-posix\*(FR is not specified.
|
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353 | T}
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354 | .T&
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355 | ls
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356 | l lw(2.2i).
|
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357 | \*(FC\-\^\-source '\*(FItext\*(FC'\*(FR
|
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358 | %use \*(FItext\*(FR as AWK program source code.
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359 | \*(FC\-\^\-version\*(FR%T{
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360 | print version information on \*(FCstdout\fP
|
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361 | and exit zero.
|
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362 | T}
|
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363 | .TE
|
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364 | .sp .5
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365 | .fi
|
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366 | In compatibility mode,
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367 | any other options are flagged as invalid, but are otherwise ignored.
|
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368 | In normal operation, as long as program text has been supplied, unknown
|
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369 | options are passed on to the AWK program in
|
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370 | \*(FCARGV\*(FR
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371 | for processing. This is most useful for running AWK
|
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372 | programs via the \*(FC#!\*(FR executable interpreter mechanism.\*(CB
|
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373 | .EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (\*(GK\f(HB)\*(FR\s0"
|
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374 |
|
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375 | .BT
|
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376 |
|
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377 | .\"
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378 | .\"
|
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379 | .\" --- Command Line Arguments (mawk)
|
---|
380 | .ES
|
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381 | .fi
|
---|
382 | \*(CDThe following options are specific to \*(MK.
|
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383 | .sp .5
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384 | .fi
|
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385 | .TS
|
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386 | expand;
|
---|
387 | l lw(1.8i).
|
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388 | \*(FC\-W dump\*(FR T{
|
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389 | print an assembly listing of the program to
|
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390 | \*(FCstdout\fP and exit zero.
|
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391 | T}
|
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392 | \*(FC\-W exec \*(FIfile\*(FR T{
|
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393 | read program text from \*(FIfile\fP. No other
|
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394 | options are processed. Useful with \*(FC#!\fP.
|
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395 | T}
|
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396 | \*(FC\-W interactive\*(FR T{
|
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397 | unbuffer \*(FCstdout\fP and line buffer \*(FCstdin\fP.
|
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398 | Lines are always records, ignoring \*(FCRS\fP.
|
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399 | T}
|
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400 | \*(FC\-W posix_space\*(FR T{
|
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401 | \*(FC\en\*(FR separates fields when \*(FCRS = "\^"\fP.
|
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402 | T}
|
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403 | \*(FC\-W sprintf=\*(FInum\*(FR T{
|
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404 | adjust the size of \*(MK's internal
|
---|
405 | \*(FCsprintf\*(FR buffer.
|
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406 | T}
|
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407 | \*(FC\-W version\*(FR T{
|
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408 | print version and copyright on
|
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409 | \*(FCstdout\fP and limit information on \*(FCstderr\fP
|
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410 | and exit zero.
|
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411 | T}
|
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412 | .TE
|
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413 | .sp .5
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414 | .fi
|
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415 | The options may be abbreviated using just the first letter, e.g.,
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416 | \*(FC\-We\*(FR,
|
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417 | \*(FC\-Wv\*(FR
|
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418 | and so on.\*(CB
|
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419 | .EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (\*(MK\f(HB)\*(FR\s0"
|
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420 | .sp .7
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421 | .\" --- Signals (pgawk)
|
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422 | .ES
|
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423 | .fi
|
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424 | \*(CD\*(PK accepts two signals.
|
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425 | \*(FCSIGUSR1\fP dumps a profile and function call stack to the
|
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426 | profile file. It then continues to run.
|
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427 | \*(FCSIGHUP\fP is similar, but exits.\*(CB
|
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428 | .EB "\s+2\f(HBSIGNALS (\*(PK\f(HB)\*(FR\s0"
|
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429 | .sp .7
|
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430 | .\" --- Awk Program Execution
|
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431 | .ES
|
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432 | .fi
|
---|
433 | \*(CDAWK programs are a sequence of pattern-action statements
|
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434 | and optional function definitions.
|
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435 | .sp .5
|
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436 | \*(FIpattern\*(FC { \*(FIaction statements\*(FC }\*(FR
|
---|
437 | .br
|
---|
438 | \*(FCfunction \*(FIname\*(FC(\*(FIparameter list\*(FC) { \*(FIstatements\*(FC }\*(FR
|
---|
439 | .sp .5
|
---|
440 | \*(AK first reads the program source from the
|
---|
441 | \*(FIprog-file\*(FR(s), if specified,
|
---|
442 | \*(CBfrom arguments to \*(FC\-\^\-source\*(FR,\*(CD
|
---|
443 | or from the first non-option argument on the command line.
|
---|
444 | The program text is read as if all the \*(FIprog-file\*(FR(s)
|
---|
445 | \*(CBand command line
|
---|
446 | source texts\*(CD had been concatenated.
|
---|
447 | .sp .5
|
---|
448 | AWK programs execute in the following order.
|
---|
449 | First, all variable assignments specified via the \*(FC\-v\fP
|
---|
450 | option are performed.
|
---|
451 | Next, \*(AK executes the code in the
|
---|
452 | \*(FCBEGIN\fP rules(s), if any, and then proceeds to read
|
---|
453 | the files \*(FC1\fP through \*(FCARGC \- 1\fP in the \*(FCARGV\fP array.
|
---|
454 | (Adjusting \*(FCARGC\fP and \*(FCARGV\fP thus provides control over
|
---|
455 | the input files that will be processed.)
|
---|
456 | If there are no files named on the command line,
|
---|
457 | \*(AK reads the standard input.
|
---|
458 | .sp .5
|
---|
459 | If a command line argument has the form
|
---|
460 | \*(FIvar\*(FC=\*(FIval\*(FR,
|
---|
461 | it is treated as a variable assignment. The variable
|
---|
462 | \*(FIvar\fP will be assigned the value \*(FIval\*(FR.
|
---|
463 | (This happens after any \*(FCBEGIN\fP rule(s) have been run.)
|
---|
464 | ... delete this paragraph if no space
|
---|
465 | Command line variable assignment
|
---|
466 | is most useful for dynamically assigning values to the variables
|
---|
467 | \*(AK uses to control how input is broken into fields and records. It
|
---|
468 | is also useful for controlling state if multiple passes are needed over
|
---|
469 | a single data file.
|
---|
470 | .sp .5
|
---|
471 | If the value of a particular element of \*(FCARGV\fP is empty
|
---|
472 | (\*(FC"\^"\*(FR), \*(AK skips over it.
|
---|
473 | .sp .5
|
---|
474 | For each record in the input, \*(AK tests to see if it matches any
|
---|
475 | \*(FIpattern\fP in the AWK program.
|
---|
476 | For each pattern that the record matches, the associated
|
---|
477 | \*(FIaction\fP is executed.
|
---|
478 | The patterns are tested in the order they occur in the program.
|
---|
479 | .sp .5
|
---|
480 | Finally, after all the input is exhausted,
|
---|
481 | \*(AK executes the code in the \*(FCEND\fP rule(s), if any.
|
---|
482 | .sp .5
|
---|
483 | If a program only has a \*(FCBEGIN\fP rule, no input files are processed.
|
---|
484 | If a program only has an \*(FCEND\fP rule, the input will be read.
|
---|
485 | \*(CX
|
---|
486 | .EB "\s+2\f(HBAWK PROGRAM EXECUTION\*(FR\s0"
|
---|
487 |
|
---|
488 |
|
---|
489 | .BT
|
---|
490 |
|
---|
491 | .\" --- Lines And Statements
|
---|
492 | .ES
|
---|
493 | .fi
|
---|
494 | \*(CDAWK is a line-oriented language. The pattern comes first, and then the
|
---|
495 | action. Action statements are enclosed in \*(FC{\fP and \*(FC}\*(FR.
|
---|
496 | Either the pattern or the action may be missing, but
|
---|
497 | not both. If the pattern is missing, the action is
|
---|
498 | executed for every input record.
|
---|
499 | A missing action is equivalent to
|
---|
500 | .sp .5
|
---|
501 | \*(FC{ print }\fP
|
---|
502 | .sp .5
|
---|
503 | which prints the entire record.
|
---|
504 | .sp .5
|
---|
505 | Comments begin with the \*(FC#\*(FR character, and continue until the
|
---|
506 | end of the line.
|
---|
507 | Normally, a statement ends with a newline, but lines ending in
|
---|
508 | a ``,'',
|
---|
509 | \*(FC{\*(FR,
|
---|
510 | \*(CB\*(FC?\*(FR,
|
---|
511 | \*(FC:\*(FR,\*(CD
|
---|
512 | \*(FC&&\*(FR
|
---|
513 | or
|
---|
514 | \*(FC||\*(FR
|
---|
515 | are automatically continued.
|
---|
516 | Lines ending in \*(FCdo\fP or \*(FCelse\fP
|
---|
517 | also have their statements automatically continued on the following line.
|
---|
518 | In other cases, a line can be continued by ending it with a ``\e'',
|
---|
519 | in which case the newline is ignored. However, a ``\e'' after a
|
---|
520 | \*(FC#\*(FR is not special.
|
---|
521 | .sp .5
|
---|
522 | Multiple statements may be put on one line by separating them with a ``;''.
|
---|
523 | This applies to both the statements within the action part of a
|
---|
524 | pattern-action pair (the usual case)
|
---|
525 | and to the pattern-action statements themselves.\*(CX
|
---|
526 | .EB "\s+2\f(HBLINES AND STATEMENTS\*(FR\s0"
|
---|
527 |
|
---|
528 |
|
---|
529 |
|
---|
530 | .\" --- Regular Expressions
|
---|
531 | .ES
|
---|
532 | .fi
|
---|
533 | \*(CDRegular expressions are the extended kind originally defined by
|
---|
534 | \*(FCegrep\fP.
|
---|
535 | \*(CBAdditional GNU regexp operators are supported by \*(GK.
|
---|
536 | A \*(FIword-constituent\fP character is a letter, digit, or
|
---|
537 | underscore (\*(FC_\fP).\*(CD
|
---|
538 | .sp .5
|
---|
539 | .TS
|
---|
540 | center, tab(~);
|
---|
541 | cp8 sp8
|
---|
542 | cp8 sp8
|
---|
543 | lp8|lp8.
|
---|
544 | .\" .vs 10
|
---|
545 | _
|
---|
546 | Summary of Regular Expressions
|
---|
547 | In Decreasing Precedence
|
---|
548 | _
|
---|
549 | \*(FC(\^\*(FIr\*(FC)\*(FR~regular expression (for grouping)
|
---|
550 | \*(FIc\*(FR~if non-special char, matches itself
|
---|
551 | \*(FC\e\*(FI\^c\*(FR~turn off special meaning of \*(FIc\fP
|
---|
552 | \*(FC^\*(FR~beginning of string (note: \*(FInot\fP line)
|
---|
553 | \*(FC$\*(FR~end of string (note: \*(FInot\fP line)
|
---|
554 | \*(FC.\*(FR~any single character, including newline
|
---|
555 | \*(FC[\*(FR...\*(FC]\*(FR~any one character in ... or range
|
---|
556 | \*(FC[^\*(FR...\*(FC]\*(FR~any one character not in ... or range
|
---|
557 | \*(CB\*(FC\ey\*(FR~word boundary
|
---|
558 | \*(FC\eB\*(FR~middle of a word
|
---|
559 | \*(FC\e<\*(FR~beginning of a word
|
---|
560 | \*(FC\e>\*(FR~end of a word
|
---|
561 | \*(FC\ew\*(FR~any word-constituent character
|
---|
562 | \*(FC\eW\*(FR~any non-word-constituent character
|
---|
563 | \*(FC\e`\*(FR~beginning of a string
|
---|
564 | \*(FC\e'\*(FR~end of a string\*(CD
|
---|
565 | \*(FIr\*(FC*\*(FR~zero or more occurrences of \*(FIr\*(FR
|
---|
566 | \*(FIr\*(FC+\*(FR~one or more occurrences of \*(FIr\*(FR
|
---|
567 | \*(FIr\*(FC?\*(FR~zero or one occurrences of \*(FIr\*(FR
|
---|
568 | \*(FIr\*(FC{\*(FIn\*(FC,\*(FIm\*(FC}\*(FR~\*(FIn\fP to \*(FIm\fP occurrences of \*(FIr\*(FR \*(CR(POSIX: see note below)\*(CD
|
---|
569 | \*(FIr1\*(FC|\|\*(FIr2\*(FR~\*(FIr1\*(FR or \*(FIr2\*(FR
|
---|
570 | .TE
|
---|
571 | .sp .5
|
---|
572 | .fi
|
---|
573 | \*(CRThe \*(FIr\*(FC{\*(FIn\*(FC,\*(FIm\*(FC}\*(FR notation is called an
|
---|
574 | \*(FIinterval expression\fP. POSIX mandates it for AWK regexps, but
|
---|
575 | most \*(AKs don't implement it. \*(CBUse \*(FC\-\^\-re\-interval\*(FR
|
---|
576 | or \*(FC\-\^\-posix\*(FR to enable
|
---|
577 | this feature in \*(GK.\*(CX
|
---|
578 | .EB "\s+2\f(HBREGULAR EXPRESSIONS\*(FR\s0"
|
---|
579 |
|
---|
580 |
|
---|
581 | .BT
|
---|
582 |
|
---|
583 | .\" --- POSIX Character Classes (gawk)
|
---|
584 | .ES
|
---|
585 | .fi
|
---|
586 | \*(CDIn regular expressions, within character ranges
|
---|
587 | (\*(FC[\*(FR...\*(FC]\*(FR),
|
---|
588 | the notation \*(FC[[:\*(FIclass\*(FC:]]\*(FR defines character classes:
|
---|
589 | .sp .5
|
---|
590 | .TS
|
---|
591 | center, tab(~);
|
---|
592 | lp8 lp8 lp8 lp8.
|
---|
593 | \*(FCalnum\*(FR~alphanumeric~\*(FClower\*(FR~lower-case
|
---|
594 | \*(FCalpha\*(FR~alphabetic~\*(FCprint\*(FR~printable
|
---|
595 | \*(FCblank\*(FR~space or tab~\*(FCpunct\*(FR~punctuation
|
---|
596 | \*(FCcntrl\*(FR~control~\*(FCspace\*(FR~whitespace
|
---|
597 | \*(FCdigit\*(FR~decimal~\*(FCupper\*(FR~upper-case
|
---|
598 | \*(FCgraph\*(FR~non-spaces~\*(FCxdigit\*(FR~hexadecimal
|
---|
599 | .TE
|
---|
600 | .fi
|
---|
601 | .sp .5
|
---|
602 | Recognition of these character classes is disabled
|
---|
603 | when \*(FC\-\-traditional\*(FR is supplied.\*(CB
|
---|
604 | .EB "\s+2\f(HBPOSIX CHARACTER CLASSES (\*(GK\f(HB)\*(FR\s0"
|
---|
605 |
|
---|
606 | .\" --- Records
|
---|
607 | .ES
|
---|
608 | .fi
|
---|
609 | \*(CDNormally, records are separated by newline characters.
|
---|
610 | Assigning values to the built-in variable \*(FCRS\*(FR
|
---|
611 | controls how records are separated.
|
---|
612 | If \*(FCRS\fP is any single character, that character separates records.
|
---|
613 | \*(CLOtherwise, \*(FCRS\fP is a regular expression.
|
---|
614 | \*(CR(Not \*(NK.)\*(CL
|
---|
615 | Text in the input that matches this
|
---|
616 | regular expression separates the record.
|
---|
617 | \*(CB\*(GK sets \*(FCRT\*(FR to the value of the
|
---|
618 | input text that matched the regular expression.
|
---|
619 | The value of \*(FCIGNORECASE\fP
|
---|
620 | also affects how records are separated when
|
---|
621 | \*(FCRS\fP is a regular expression.\*(CD
|
---|
622 | If \*(FCRS\fP is set to the null string,
|
---|
623 | then records are separated by one or more blank lines.
|
---|
624 | When \*(FCRS\fP is set to the null string,
|
---|
625 | the newline character always acts as
|
---|
626 | a field separator, in addition to whatever value
|
---|
627 | \*(FCFS\fP may have.
|
---|
628 | \*(CB\*(MK does not apply exceptional rules to \*(FCFS\fP
|
---|
629 | when \*(FCRS = "\^"\fP.\*(CX
|
---|
630 | .EB "\s+2\f(HBRECORDS\*(FR\s0"
|
---|
631 |
|
---|
632 | .\" --- Fields
|
---|
633 | .ES
|
---|
634 | .fi
|
---|
635 | \*(CDAs each input record is read, \*(AK splits the record into
|
---|
636 | \*(FIfields\*(FR, using the value of the \*(FCFS\fP
|
---|
637 | variable as the field separator.
|
---|
638 | If \*(FCFS\fP is a single character,
|
---|
639 | fields are separated by that character.
|
---|
640 | \*(CLIf \*(FCFS\fP is the null string,
|
---|
641 | then each individual character becomes a separate field.\*(CD
|
---|
642 | Otherwise, \*(FCFS\fP is expected to be a full regular expression.
|
---|
643 | In the special case that \*(FCFS\fP
|
---|
644 | is a single space, fields are separated
|
---|
645 | by runs of spaces and/or tabs
|
---|
646 | \*(CLand/or newlines\*(CD.
|
---|
647 | Leading and trailing whitespace are ignored.
|
---|
648 | \*(CBThe value of \*(FCIGNORECASE\fP
|
---|
649 | also affects how fields are split when
|
---|
650 | \*(FCFS\fP is a regular expression.\*(CD
|
---|
651 | .sp .5
|
---|
652 | \*(CBIf the \*(FCFIELDWIDTHS\fP
|
---|
653 | variable is set to a space-separated list of numbers, each field is
|
---|
654 | expected to have a fixed width, and \*(GK
|
---|
655 | splits up the record using the specified widths.
|
---|
656 | The value of \*(FCFS\fP is ignored.
|
---|
657 | Assigning a new value to \*(FCFS\fP
|
---|
658 | overrides the use of \*(FCFIELDWIDTHS\*(FR,
|
---|
659 | and restores the default behavior.\*(CD
|
---|
660 | .sp .5
|
---|
661 | Each field in the input record may be referenced by its position,
|
---|
662 | \*(FC$1\*(FR, \*(FC$2\*(FR and so on.
|
---|
663 | \*(FC$0\fP is the whole record.
|
---|
664 | Fields may also be assigned new values.
|
---|
665 | .sp .5
|
---|
666 | The variable \*(FCNF\fP
|
---|
667 | is set to the total number of fields in the input record.
|
---|
668 | .sp .5
|
---|
669 | References to non-existent fields (i.e., fields after \*(FC$NF\*(FR)
|
---|
670 | produce the null-string. However, assigning to a non-existent field
|
---|
671 | (e.g., \*(FC$(NF+2) = 5\*(FR) increases the value of
|
---|
672 | \*(FCNF\*(FR, creates any intervening fields with the null string as their value,
|
---|
673 | and causes the value of \*(FC$0\fP
|
---|
674 | to be recomputed with the fields being separated by the
|
---|
675 | value of \*(FCOFS\*(FR.
|
---|
676 | References to negative numbered fields cause a fatal error.
|
---|
677 | Decreasing the value of \*(FCNF\fP causes the trailing fields to be lost
|
---|
678 | \*(CR(not \*(NK).\*(CX
|
---|
679 | .EB "\s+2\f(HBFIELDS\*(FR\s0"
|
---|
680 |
|
---|
681 | .BT
|
---|
682 |
|
---|
683 | .\" --- Pattern Elements
|
---|
684 | .ES
|
---|
685 | .fi
|
---|
686 | \*(CDAWK patterns may be one of the following.
|
---|
687 | .sp .5
|
---|
688 | .nf
|
---|
689 | \*(FCBEGIN
|
---|
690 | END
|
---|
691 | \*(FIexpression
|
---|
692 | pat1\*(FC,\*(FIpat2\*(FR
|
---|
693 | .sp .5
|
---|
694 | .fi
|
---|
695 | \*(FCBEGIN\fP and \*(FCEND\fP are special patterns that provide start-up
|
---|
696 | and clean-up actions respectively. They must have actions. There can
|
---|
697 | be multiple \*(FCBEGIN\fP and \*(FCEND\fP rules; they are merged and
|
---|
698 | executed as if there had just been one large rule. They may occur anywhere
|
---|
699 | in a program, including different source files.
|
---|
700 | .sp .5
|
---|
701 | Expression patterns can be any expression, as described
|
---|
702 | under \fHExpressions\fP.
|
---|
703 | .sp .5
|
---|
704 | The \*(FIpat1\*(FC,\*(FIpat2\*(FR pattern
|
---|
705 | is called a \*(FIrange pattern\*(FR.
|
---|
706 | It matches all input records starting with a record that matches
|
---|
707 | \*(FIpat1\*(FR, and continuing until a record that matches
|
---|
708 | \*(FIpat2\*(FR, inclusive.
|
---|
709 | It does not combine with any other pattern expression.\*(CX
|
---|
710 | .EB "\s+2\f(HBPATTERN ELEMENTS\*(FR\s0"
|
---|
711 |
|
---|
712 |
|
---|
713 | .\" --- Action Statements
|
---|
714 | .ES
|
---|
715 | .fi
|
---|
716 | .in +.2i
|
---|
717 | .ti -.2i
|
---|
718 | \*(CD\*(FCbreak\*(FR
|
---|
719 | .br
|
---|
720 | break out of the nearest enclosing \*(FCdo\*(FR, \*(FCfor\*(FR,
|
---|
721 | or \*(FCwhile\*(FR loop.
|
---|
722 | .ti -.2i
|
---|
723 | \*(FCcontinue\*(FR
|
---|
724 | .br
|
---|
725 | skip the rest of the loop body.
|
---|
726 | Evaluate the \*(FIcondition\*(FR
|
---|
727 | part of the nearest enclosing \*(FCdo\*(FR or \*(FCwhile\*(FR loop,
|
---|
728 | or go to the \*(FIincr\*(FR part of a \*(FCfor\*(FR loop.
|
---|
729 | .ti -.2i
|
---|
730 | \*(FCdelete \*(FIarray\^\*(FC[\^\*(FIindex\^\*(FC]\*(FR
|
---|
731 | .br
|
---|
732 | delete element \*(FIindex\*(FR from array \*(FIarray\*(FR.
|
---|
733 | .ti -.2i
|
---|
734 | \*(CL\*(FCdelete \*(FIarray\^\*(FR
|
---|
735 | .br
|
---|
736 | delete all elements from array \*(FIarray\*(FR.\*(CD
|
---|
737 | .ti -.2i
|
---|
738 | \*(FCdo \*(FIstatement \*(FCwhile (\*(FIcondition\*(FC)\*(FR
|
---|
739 | .br
|
---|
740 | execute \*(FIstatement\*(FR while \*(FIcondition\*(FR is true.
|
---|
741 | The \*(FIstatement\*(FR is always executed at least once.
|
---|
742 | .ti -.2i
|
---|
743 | \*(FCexit\*(FR [ \*(FIexpression\*(FR ]
|
---|
744 | .br
|
---|
745 | terminate input record processing.
|
---|
746 | Execute the \*(FCEND\*(FR rule(s) if present.
|
---|
747 | If present, \*(FIexpression\*(FR becomes \*(AK's return value.
|
---|
748 | .ti -.2i
|
---|
749 | \*(FCfor (\*(FIinit\*(FC; \*(FIcond\*(FC; \*(FIincr\*(FC) \*(FIstatement\*(FR
|
---|
750 | .br
|
---|
751 | execute \*(FIinit\*(FR.
|
---|
752 | Evaluate \*(FIcond\*(FR.
|
---|
753 | If it is true, execute \*(FIstatement\*(FR.
|
---|
754 | Execute \*(FIincr\*(FR before going back to the top to
|
---|
755 | re-evaluate \*(FIcond\*(FR.
|
---|
756 | Any of the three may be omitted.
|
---|
757 | A missing \*(FIcond\*(FR is considered to be true.
|
---|
758 | .ti -.2i
|
---|
759 | \*(FCfor (\*(FIvar \*(FCin\*(FI array\*(FC) \*(FIstatement\*(FR
|
---|
760 | .br
|
---|
761 | execute \*(FIstatement\*(FR once for each subscript in \*(FIarray\*(FR,
|
---|
762 | with \*(FIvar\*(FR set to a different subscript each time through
|
---|
763 | the loop.
|
---|
764 | .ti -.2i
|
---|
765 | \*(CD\*(FCif (\*(FIcondition\*(FC) \*(FIstatement1\*(FR [ \*(FCelse\*(FI statement2\*(FR ]
|
---|
766 | .br
|
---|
767 | if \*(FIcondition\*(FR is true, execute \*(FIstatement1\*(FR,
|
---|
768 | otherwise execute \*(FIstatement2\*(FR. Each \*(FCelse\*(FR
|
---|
769 | matches the closest \*(FCif\*(FR.
|
---|
770 | .ti -.2i
|
---|
771 | \*(FCnext\*(FR see \fHInput Control.\fP
|
---|
772 | .ti -.2i
|
---|
773 | \*(CL\*(FCnextfile\*(FR \*(CR(not \*(MK) \*(CLsee \fHInput Control.\fP\*(CD
|
---|
774 | .ti -.2i
|
---|
775 | .\" --- Start switch statement
|
---|
776 | \*(CB\*(FCswitch (\*(FIexpression\*(FC) {
|
---|
777 | .br
|
---|
778 | case [\*(FIvalue\*(FC|\*(FIregular expression\*(FC] : \*(FIstatement(s)\*(FC
|
---|
779 | .br
|
---|
780 | default: \*(FIstatement(s)\*(FC
|
---|
781 | .br
|
---|
782 | }\*(FR
|
---|
783 | .br
|
---|
784 | switch on \*(FIexpression\*(FR, execute \*(FIcase\*(FR if matched, default if not.
|
---|
785 | For 3.1.x, requires \*(FC\-\^\-enable\-switch\*(FR option to \*(FCconfigure\*(FR.\*(CD
|
---|
786 | .ti -.2i
|
---|
787 | .\" --- End switch statement
|
---|
788 | \*(FCwhile (\*(FIcondition\*(FC) \*(FIstatement \*(FR
|
---|
789 | .br
|
---|
790 | while \*(FIcondition\*(FR is true, execute \*(FIstatement\*(FR.
|
---|
791 | .ti -.2i
|
---|
792 | \*(FC{ \*(FIstatements \*(FC}\*(FR
|
---|
793 | .br
|
---|
794 | a list of statements enclosed in braces can be used anywhere
|
---|
795 | that a single statement would otherwise be used.\*(CX
|
---|
796 | .in -.2i
|
---|
797 | .EB "\s+2\f(HBACTION STATEMENTS\*(FR\s0"
|
---|
798 |
|
---|
799 |
|
---|
800 | .BT
|
---|
801 |
|
---|
802 | .\" --- Escape Sequences
|
---|
803 | .ES
|
---|
804 | .fi
|
---|
805 | \*(CDWithin strings constants (\*(FC"..."\fP) and regexp
|
---|
806 | constants (\*(FC/.../\fP), escape sequences may be used to
|
---|
807 | generate otherwise unprintable characters. This table lists
|
---|
808 | the available escape sequences.
|
---|
809 | .sp .5
|
---|
810 | .TS
|
---|
811 | center, tab(~);
|
---|
812 | lp8 lp8 lp8 lp8.
|
---|
813 | \*(FC\ea\fP~alert (bell)~\*(FC\er\fP~carriage return
|
---|
814 | \*(FC\eb\fP~backspace~\*(FC\et\fP~horizontal tab
|
---|
815 | \*(FC\ef\fP~form feed~\*(FC\ev\fP~vertical tab
|
---|
816 | \*(FC\en\fP~newline~\*(FC\e\e\fP~backslash
|
---|
817 | \*(FC\e\*(FIddd\*(FR~octal value \*(FIddd\fP~\*(CL\*(FC\ex\*(FIhh\*(FR~hex value \*(FIhh\fP\*(CD
|
---|
818 | \*(FC\e"\fP~double quote~\*(FC\e/\fP~forward slash\*(CX
|
---|
819 | .TE
|
---|
820 | .EB "\s+2\f(HBESCAPE SEQUENCES\*(FR\s0"
|
---|
821 | .sp .7
|
---|
822 | .\" --- Variables
|
---|
823 | .ES
|
---|
824 | .fi
|
---|
825 | .TS
|
---|
826 | expand;
|
---|
827 | l lw(2i).
|
---|
828 | \*(CD\*(FCARGC\fP T{
|
---|
829 | number of command line arguments.
|
---|
830 | T}
|
---|
831 | \*(CB\*(FCARGIND\fP T{
|
---|
832 | index in \*(FCARGV\fP of current data file.\*(CD
|
---|
833 | T}
|
---|
834 | \*(FCARGV\fP T{
|
---|
835 | array of command line arguments. Indexed from
|
---|
836 | 0 to \*(FCARGC\fP \- 1. Dynamically changing the
|
---|
837 | contents of \*(FCARGV\fP can control the files used
|
---|
838 | for data.
|
---|
839 | T}
|
---|
840 | \*(CL\*(FCBINMODE\fP T{
|
---|
841 | controls ``binary'' mode for all file I/O. Values of 1, 2, or 3,
|
---|
842 | indicate input, output, or all files, respectively, should use binary
|
---|
843 | I/O. \*(CR(Not \*(NK.) \*(CLApplies only to non-POSIX systems.
|
---|
844 | \*(CBFor \*(GK, string values of \*(FC"r"\fP, or \*(FC"w"\fP specify
|
---|
845 | that input files, or output files, respectively, should use binary I/O.
|
---|
846 | String values of \*(FC"rw"\fP or \*(FC"wr"\fP specify that all files
|
---|
847 | should use binary I/O. Any other string value is treated as \*(FC"rw"\fP,
|
---|
848 | but generates a warning message.\*(CD
|
---|
849 | T}
|
---|
850 | \*(FCCONVFMT\fP T{
|
---|
851 | conversion format for numbers, default value
|
---|
852 | is \*(FC"%.6g"\*(FR.
|
---|
853 | T}
|
---|
854 | \*(FCENVIRON\fP T{
|
---|
855 | array containing the current environment.
|
---|
856 | The array is indexed by the environment
|
---|
857 | variables, each element being the value of
|
---|
858 | that variable.
|
---|
859 | T}
|
---|
860 | \*(CB\*(FCERRNO\fP T{
|
---|
861 | string describing the error if a
|
---|
862 | \*(FCgetline\*(FR
|
---|
863 | redirection or read
|
---|
864 | fails, or if
|
---|
865 | \*(FCclose()\*(FR fails.
|
---|
866 | T}
|
---|
867 | \*(FCFIELDWIDTHS\fP T{
|
---|
868 | white-space separated list of fieldwidths. Used
|
---|
869 | to parse the input into fields of fixed width,
|
---|
870 | instead of the value of \*(FCFS\fP.\*(CD
|
---|
871 | T}
|
---|
872 | \*(FCFILENAME\fP T{
|
---|
873 | name of the current input file. If no files given
|
---|
874 | on the command line, \*(FCFILENAME\fP is ``\-''.
|
---|
875 | \*(FCFILENAME\fP is undefined inside the \*(FCBEGIN\fP rule
|
---|
876 | (unless set by \*(FCgetline\fP).
|
---|
877 | T}
|
---|
878 | \*(FCFNR\fP T{
|
---|
879 | record number in current input file.
|
---|
880 | T}
|
---|
881 | \*(FCFS\fP T{
|
---|
882 | input field separator, a space by default
|
---|
883 | (see \fHFields\fP above).
|
---|
884 | T}
|
---|
885 | \*(CB\*(FCIGNORECASE\fP T{
|
---|
886 | if non-zero, all regular expression and string
|
---|
887 | operations ignore case.
|
---|
888 | Array subscripting
|
---|
889 | is \*(FInot\*(FR affected.
|
---|
890 | However, the
|
---|
891 | \*(FCasort()\*(FR
|
---|
892 | and
|
---|
893 | \*(FCasorti()\*(FR
|
---|
894 | function are affected.
|
---|
895 | T}
|
---|
896 | \*(CB\*(FCLINT\fP T{
|
---|
897 | provides dynamic control of the \*(FC\-\^\-lint\fP
|
---|
898 | option from within an AWK program.
|
---|
899 | When true, \*(GK
|
---|
900 | prints lint warnings.
|
---|
901 | When assigned the string value \*(FC"fatal"\*(FR,
|
---|
902 | lint warnings become fatal errors, exactly like
|
---|
903 | \*(FC\-\-lint=fatal\*(FR.
|
---|
904 | Any other true value just prints warnings.\*(CD
|
---|
905 | T}
|
---|
906 | \*(FCNF\fP T{
|
---|
907 | number of fields in the current input record.
|
---|
908 | T}
|
---|
909 | \*(FCNR\fP T{
|
---|
910 | total number of input records seen so far.\*(CX
|
---|
911 | T}
|
---|
912 | .TE
|
---|
913 | .EB "\s+2\f(HBVARIABLES\*(FR\s0"
|
---|
914 | .BT
|
---|
915 |
|
---|
916 | .\" --- Variables (continued)
|
---|
917 | .ES
|
---|
918 | .fi
|
---|
919 | .TS
|
---|
920 | expand;
|
---|
921 | l lw(2i).
|
---|
922 | \*(CD\*(FCOFMT\fP T{
|
---|
923 | output format for numbers, \*(FC"%.6g"\*(FR, by default.
|
---|
924 | \*(CROld versions of \*(AK used this for number
|
---|
925 | to string conversion.\*(CD
|
---|
926 | T}
|
---|
927 | \*(FCOFS\fP T{
|
---|
928 | output field separator, a space by default.
|
---|
929 | T}
|
---|
930 | \*(FCORS\fP T{
|
---|
931 | output record separator, a newline by default.
|
---|
932 | T}
|
---|
933 | \*(CB\*(FCPROCINFO\fP T{
|
---|
934 | elements of this array provide access to info
|
---|
935 | about the running AWK program. See
|
---|
936 | \*(AM for details.\*(CD
|
---|
937 | T}
|
---|
938 | \*(FCRLENGTH\fP T{
|
---|
939 | length of the string matched by \*(FCmatch()\*(FR;
|
---|
940 | \-1 if no match.
|
---|
941 | T}
|
---|
942 | \*(FCRS\fP T{
|
---|
943 | input record separator, a newline by default
|
---|
944 | (see \fHRecords\fP above).
|
---|
945 | T}
|
---|
946 | \*(FCRSTART\fP T{
|
---|
947 | index of the first character matched by
|
---|
948 | \*(FCmatch()\*(FR; 0 if no match.
|
---|
949 | T}
|
---|
950 | \*(CB\*(FCRT\fP T{
|
---|
951 | record terminator. \*(GK sets \*(FCRT\fP to the input
|
---|
952 | text that matched the character or regular
|
---|
953 | expression specified by \*(FCRS\*(FR.\*(CD
|
---|
954 | T}
|
---|
955 | \*(FCSUBSEP\fP T{
|
---|
956 | character(s) used to separate multiple subscripts
|
---|
957 | in array elements, by default \*(FC"\e034"\*(FR. (See
|
---|
958 | \fHArrays\fP below).
|
---|
959 | T}
|
---|
960 | \*(CB\*(FCTEXTDOMAIN\fP T{
|
---|
961 | the application's text domain for internationalization;
|
---|
962 | used to find the localized
|
---|
963 | translations for the program's strings.\*(CX
|
---|
964 | T}
|
---|
965 | .TE
|
---|
966 | .EB "\s+2\f(HBVARIABLES (continued)\*(FR\s0"
|
---|
967 |
|
---|
968 | .\" --- Conversions and Comparisons
|
---|
969 | .ES
|
---|
970 | .fi
|
---|
971 | \*(CDVariables and fields may be (floating point) numbers, strings or both.
|
---|
972 | Context determines how the value of a variable is interpreted. If used in
|
---|
973 | a numeric expression, it will be treated as a number, if used as a string
|
---|
974 | it will be treated as a string.
|
---|
975 | .sp .5
|
---|
976 | To force a variable to be treated as a number, add 0 to it; to force it
|
---|
977 | to be treated as a string, concatenate it with the null string.
|
---|
978 | .sp .5
|
---|
979 | When a string must be converted to a number, the conversion is accomplished
|
---|
980 | using \*(FIstrtod\*(FR(3).
|
---|
981 | A number is converted to a string by using the value of \*(FCCONVFMT\fP
|
---|
982 | as a format string for \*(FIsprintf\*(FR(3),
|
---|
983 | with the numeric value of the variable as the argument.
|
---|
984 | However, even though all numbers in AWK are floating-point,
|
---|
985 | integral values are \*(FIalways\fP converted as integers.
|
---|
986 | .sp .5
|
---|
987 | Comparisons are performed as follows:
|
---|
988 | If two variables are numeric, they are compared numerically.
|
---|
989 | If one value is numeric and the other has a string value that is a
|
---|
990 | ``numeric string,'' then comparisons are also done numerically.
|
---|
991 | Otherwise, the numeric value is converted to a string, and a string
|
---|
992 | comparison is performed.
|
---|
993 | Two strings are compared, of course, as strings.
|
---|
994 | .sp .5
|
---|
995 | Note that string constants, such as \*(FC"57"\fP, are \*(FInot\fP
|
---|
996 | numeric strings, they are string constants. The idea of ``numeric string''
|
---|
997 | only applies to fields, \*(FCgetline\fP input,
|
---|
998 | \*(FCFILENAME\*(FR, \*(FCARGV\fP elements, \*(FCENVIRON\fP
|
---|
999 | elements and the elements of an array created by
|
---|
1000 | \*(FCsplit()\fP that are numeric strings.
|
---|
1001 | The basic idea is that \*(FIuser input\*(FR,
|
---|
1002 | and only user input, that looks numeric,
|
---|
1003 | should be treated that way.
|
---|
1004 | \*(CRNote that the POSIX standard applies the concept of
|
---|
1005 | ``numeric string'' everywhere, even to string constants.
|
---|
1006 | However, this is
|
---|
1007 | clearly incorrect, and none of the three free \*(AK\*(FRs do this.\*(CD
|
---|
1008 | (Fortunately, this is fixed in the next version of the standard.)
|
---|
1009 | .sp .5
|
---|
1010 | Uninitialized variables have the numeric value 0 and the string value
|
---|
1011 | \*(FC"\^"\fP
|
---|
1012 | (the null, or empty, string).\*(CX
|
---|
1013 | .EB "\s+2\f(HBCONVERSIONS AND COMPARISONS\*(FR\s0"
|
---|
1014 |
|
---|
1015 | .BT
|
---|
1016 |
|
---|
1017 | .\" --- Historical Features
|
---|
1018 | .ES
|
---|
1019 | .fi
|
---|
1020 | \*(CD1. It is possible to call the \*(FClength()\fP
|
---|
1021 | built-in function not only with no argument, but even without parentheses.
|
---|
1022 | This feature is marked as ``deprecated'' in the POSIX standard, and \*(GK
|
---|
1023 | issues a warning about its use if \*(FC\-\^\-lint\fP
|
---|
1024 | is specified on the command line.
|
---|
1025 | .sp .5
|
---|
1026 | 2. The \*(FCcontinue\fP
|
---|
1027 | and \*(FCbreak\fP statements may be used outside the body of a
|
---|
1028 | \*(FCwhile\*(FR, \*(FCfor\*(FR, or \*(FCdo\fP loop.
|
---|
1029 | Historical AWK implementations have treated such usage as
|
---|
1030 | equivalent to the \*(FCnext\fP statement.
|
---|
1031 | \*(GK supports this usage if \*(FC\-\^\-traditional\fP
|
---|
1032 | is specified.\*(CB
|
---|
1033 | .EB "\s+2\f(HBHISTORICAL FEATURES (\*(GK\f(HB)\*(FR\s0"
|
---|
1034 |
|
---|
1035 | .ES
|
---|
1036 | \*(CX
|
---|
1037 | .sp 47
|
---|
1038 | .EB "\s+2\f(HBNOTES\*(FR\s0"
|
---|
1039 |
|
---|
1040 | .BT
|
---|
1041 |
|
---|
1042 | .\" --- Arrays
|
---|
1043 | .ES
|
---|
1044 | .fi
|
---|
1045 | \*(CDAn array subscript is an expression between square brackets
|
---|
1046 | (\*(FC[ \*(FRand \*(FC]\*(FR).
|
---|
1047 | If the expression is a list
|
---|
1048 | (\*(FIexpr\*(FC, \*(FIexpr \*(FR...),
|
---|
1049 | then the subscript is a string consisting of the
|
---|
1050 | concatenation of the (string) value of each expression,
|
---|
1051 | separated by the value of the \*(FCSUBSEP\fP variable.
|
---|
1052 | This simulates multi-dimensional
|
---|
1053 | arrays. For example:
|
---|
1054 | .nf
|
---|
1055 | .sp .5
|
---|
1056 | \*(FCi = "A";\^ j = "B";\^ k = "C"
|
---|
1057 | x[i, j, k] = "hello, world\en"\*(FR
|
---|
1058 | .sp .5
|
---|
1059 | .fi
|
---|
1060 | assigns \*(FC"hello, world\en"\*(FR to the element of the array
|
---|
1061 | \*(FCx\fP
|
---|
1062 | indexed by the string \*(FC"A\e034B\e034C"\*(FR. All arrays in AWK
|
---|
1063 | are associative, i.e., indexed by string values.
|
---|
1064 | .sp .5
|
---|
1065 | Use the special operator \*(FCin\fP in an \*(FCif\fP
|
---|
1066 | or \*(FCwhile\fP statement to see if a particular value is
|
---|
1067 | an array index.
|
---|
1068 | .sp .5
|
---|
1069 | .nf
|
---|
1070 | \*(FCif (val in array)
|
---|
1071 | print array[val]\*(FR
|
---|
1072 | .sp .5
|
---|
1073 | .fi
|
---|
1074 | If the array has multiple subscripts, use
|
---|
1075 | \*(FC(i, j) in array\*(FR.
|
---|
1076 | .sp .5
|
---|
1077 | Use the \*(FCin\fP construct in a \*(FCfor\fP
|
---|
1078 | loop to iterate over all the elements of an array.
|
---|
1079 | .sp .5
|
---|
1080 | Use the \*(FCdelete\fP statement to delete an
|
---|
1081 | element from an array.
|
---|
1082 | \*(CLSpecifying just the array name without a subscript in
|
---|
1083 | the \*(FCdelete\fP
|
---|
1084 | statement deletes the entire contents of an array.\*(CX
|
---|
1085 | .EB "\s+2\f(HBARRAYS\*(FR\s0"
|
---|
1086 |
|
---|
1087 | .\" --- Expressions
|
---|
1088 | .ES
|
---|
1089 | .fi
|
---|
1090 | \*(CDExpressions are used as patterns, for controlling conditional action
|
---|
1091 | statements, and to produce parameter values when calling functions.
|
---|
1092 | Expressions may also be used as simple statements,
|
---|
1093 | particularly if they have side-effects such as assignment.
|
---|
1094 | Expressions mix \*(FIoperands\fP and \*(FIoperators\fP. Operands are
|
---|
1095 | constants, fields, variables, array elements, and the return
|
---|
1096 | values from function calls (both built-in and user-defined).
|
---|
1097 | .sp .5
|
---|
1098 | Regexp constants (\*(FC/\*(FIpat\*(FC/\*(FR), when used as simple expressions,
|
---|
1099 | i.e., not used on the right-hand side of
|
---|
1100 | \*(FC~\fP and \*(FC!~\fP, or as arguments to the
|
---|
1101 | \*(CB\*(FCgensub()\fP,\*(CD
|
---|
1102 | \*(FCgsub()\fP,
|
---|
1103 | \*(FCmatch()\fP,
|
---|
1104 | \*(FCsplit()\fP,
|
---|
1105 | and
|
---|
1106 | \*(FCsub()\fP,
|
---|
1107 | functions, mean \*(FC$0 ~ /\*(FIpat\*(FC/\*(FR.
|
---|
1108 | .sp .5
|
---|
1109 | The AWK operators, in order of decreasing precedence, are:
|
---|
1110 | .sp .5
|
---|
1111 | .fi
|
---|
1112 | .TS
|
---|
1113 | expand;
|
---|
1114 | l lw(1.8i).
|
---|
1115 | \*(FC(\&...)\*(FR grouping
|
---|
1116 | \*(FC$\fP field reference
|
---|
1117 | \*(FC++ \-\^\-\fP T{
|
---|
1118 | increment and decrement,
|
---|
1119 | prefix and postfix
|
---|
1120 | T}
|
---|
1121 | \*(FC^\fP \*(CL\*(FC**\*(FR\*(CD exponentiation
|
---|
1122 | \*(FC+ \- !\fP unary plus, unary minus, and logical negation
|
---|
1123 | \*(FC* / %\fP multiplication, division, and modulus
|
---|
1124 | \*(FC+ \-\fP addition and subtraction
|
---|
1125 | \*(FIspace\fP string concatenation
|
---|
1126 | \*(FC< >\fP less than, greater than
|
---|
1127 | \*(FC<= >=\fP less than or equal, greater than or equal
|
---|
1128 | \*(FC!= ==\fP not equal, equal
|
---|
1129 | \*(FC~ !~\fP regular expression match, negated match
|
---|
1130 | \*(FCin\fP array membership
|
---|
1131 | \*(FC&&\fP logical AND, short circuit
|
---|
1132 | \*(FC||\fP logical OR, short circuit
|
---|
1133 | \*(FC?\^:\fP in-line conditional expression
|
---|
1134 | .T&
|
---|
1135 | l s
|
---|
1136 | l lw(1.8i).
|
---|
1137 | \*(FC=\0+=\0\-=\0*=\0/=\0%=\0^=\0\*(CL**=\*(CD\fP
|
---|
1138 | assignment operators\*(CX
|
---|
1139 | .TE
|
---|
1140 | .EB "\s+2\f(HBEXPRESSIONS\*(FR\s0"
|
---|
1141 |
|
---|
1142 | .BT
|
---|
1143 |
|
---|
1144 | .\" --- Input Control
|
---|
1145 | .ES
|
---|
1146 | .fi
|
---|
1147 | .TS
|
---|
1148 | expand;
|
---|
1149 | l lw(1.8i).
|
---|
1150 | \*(FCgetline\fP T{
|
---|
1151 | set \*(FC$0\fP from next record;
|
---|
1152 | set \*(FCNF\*(FR, \*(FCNR\*(FR, \*(FCFNR\*(FR.
|
---|
1153 | T}
|
---|
1154 | \*(FCgetline < \*(FIfile\*(FR set \*(FC$0\fP from next record of \*(FIfile\*(FR; set \*(FCNF\*(FR.
|
---|
1155 | \*(FCgetline \*(FIv\*(FR T{
|
---|
1156 | set \*(FIv\fP from next input record;
|
---|
1157 | set \*(FCNR\*(FR, \*(FCFNR\*(FR.
|
---|
1158 | T}
|
---|
1159 | \*(FCgetline \*(FIv \*(FC< \*(FIfile\*(FR set \*(FIv\fP from next record of \*(FIfile\*(FR.
|
---|
1160 | \*(FIcmd \*(FC| getline\*(FR pipe into \*(FCgetline\*(FR; set \*(FC$0\*(FR, \*(FCNF\*(FR.
|
---|
1161 | \*(FIcmd \*(FC| getline \*(FIv\*(FR pipe into \*(FCgetline\*(FR; set \*(FIv\*(FR.
|
---|
1162 | \*(CB\*(FIcmd \*(FC|& getline\*(FR co-process pipe into \*(FCgetline\*(FR; set \*(FC$0\*(FR, \*(FCNF\*(FR.
|
---|
1163 | .TE
|
---|
1164 | .fi
|
---|
1165 | .in +.2i
|
---|
1166 | .ti -.2i
|
---|
1167 | \*(FIcmd \*(FC|& getline \*(FIv\*(FR
|
---|
1168 | .br
|
---|
1169 | co-process pipe into \*(FCgetline\*(FR; set \*(FIv\*(FR.
|
---|
1170 | .ti -.2i
|
---|
1171 | \*(FCnext\fP
|
---|
1172 | .br
|
---|
1173 | stop processing the current input
|
---|
1174 | record. Read next input record and
|
---|
1175 | start over with the first pattern in the
|
---|
1176 | program. Upon end of the input data,
|
---|
1177 | execute any \*(FCEND\fP rule(s).
|
---|
1178 | .br
|
---|
1179 | .ti -.2i
|
---|
1180 | \*(CL\*(FCnextfile\fP
|
---|
1181 | .br
|
---|
1182 | stop processing the current input file.
|
---|
1183 | The next input record comes from the
|
---|
1184 | next input file. \*(FCFILENAME\fP \*(CBand
|
---|
1185 | \*(FCARGIND\fP\*(CL are updated, \*(FCFNR\fP is reset to 1,
|
---|
1186 | and processing starts over with the first
|
---|
1187 | pattern in the AWK program. Upon end
|
---|
1188 | of input data, execute any \*(FCEND\fP rule(s).
|
---|
1189 | \*(CREarlier versions of \*(GK used
|
---|
1190 | \*(FCnext file\*(FR, as two words.
|
---|
1191 | This usage is no longer supported.
|
---|
1192 | \*(CR\*(MK does not currently support \*(FCnextfile\*(FR.\*(CD
|
---|
1193 | .in -.2i
|
---|
1194 | .sp .5
|
---|
1195 | .fi
|
---|
1196 | \*(FCgetline\*(FR returns 0 on end of file and \-1 on an error.
|
---|
1197 | \*(CBUpon an error, \*(FCERRNO\*(FR contains a string describing
|
---|
1198 | the problem.\*(CX
|
---|
1199 | .EB "\s+2\f(HBINPUT CONTROL\*(FR\s0"
|
---|
1200 |
|
---|
1201 | .\" --- Output Control
|
---|
1202 | .ES
|
---|
1203 | .fi
|
---|
1204 | .in +.2i
|
---|
1205 | .ti -.2i
|
---|
1206 | \*(CL\*(FCfflush(\*(FR[\*(FIfile\^\*(FR]\*(FC)\*(FR
|
---|
1207 | .br
|
---|
1208 | flush any buffers associated
|
---|
1209 | with the open output file or pipe \*(FIfile\*(FR.\*(CD
|
---|
1210 | \*(CBIf no \*(FIfile\fP, then flush standard output.
|
---|
1211 | If \*(FIfile\fP is null, then flush all open output files and pipes
|
---|
1212 | \*(CR(not \*(NK)\*(CD.
|
---|
1213 | .ti -.2i
|
---|
1214 | \*(FCprint\fP
|
---|
1215 | .br
|
---|
1216 | print the current record. Terminate output record
|
---|
1217 | with \*(FCORS\fP.
|
---|
1218 | .ti -.2i
|
---|
1219 | \*(FCprint \*(FIexpr-list\*(FR
|
---|
1220 | .br
|
---|
1221 | print expressions. Each expression is separated
|
---|
1222 | by the value of \*(FCOFS\fP. Terminate the output record
|
---|
1223 | with \*(FCORS\fP.
|
---|
1224 | .ti -.2i
|
---|
1225 | \*(FCprintf \*(FIfmt\*(FC, \*(FIexpr-list\*(FR
|
---|
1226 | .br
|
---|
1227 | format and print (see \fHPrintf Formats\fP below).
|
---|
1228 | .ti -.2i
|
---|
1229 | \*(FCsystem(\*(FIcmd\*(FC)\*(FR
|
---|
1230 | .br
|
---|
1231 | execute the command \*(FIcmd\*(FR,
|
---|
1232 | and return the exit status
|
---|
1233 | \*(CR(may not be available on non-POSIX systems)\*(CD.
|
---|
1234 | .sp .5
|
---|
1235 | .in -.2i
|
---|
1236 | I/O redirections may be used with both \*(FCprint\fP and \*(FCprintf\fP.
|
---|
1237 | .sp .5
|
---|
1238 | .in +.2i
|
---|
1239 | .ti -.2i
|
---|
1240 | \*(CD\*(FCprint "hello" > \*(FIfile\*(FR
|
---|
1241 | .br
|
---|
1242 | print data to \*(FIfile\fP. The first time the file is written to, it
|
---|
1243 | is truncated. Subsequent commands append data.
|
---|
1244 | .ti -.2i
|
---|
1245 | \*(FCprint "hello" >> \*(FIfile\*(FR
|
---|
1246 | .br
|
---|
1247 | append data to \*(FIfile\fP. The previous contents of \*(FIfile\*(FR are not lost.
|
---|
1248 | .ti -.2i
|
---|
1249 | \*(FCprint "hello" | \*(FIcmd\*(FR
|
---|
1250 | .br
|
---|
1251 | print data down a pipeline to \*(FIcmd\*(FR.
|
---|
1252 | .ti -.2i
|
---|
1253 | \*(CB\*(FCprint "hello" |& \*(FIcmd\*(FR
|
---|
1254 | .br
|
---|
1255 | print data down a pipeline to co-process \*(FIcmd\*(FR.\*(CX
|
---|
1256 | .in -.2i
|
---|
1257 | .EB "\s+2\f(HBOUTPUT CONTROL\*(FR\s0"
|
---|
1258 |
|
---|
1259 | .ES
|
---|
1260 | .fi
|
---|
1261 | .in +.2i
|
---|
1262 | .ti -.2i
|
---|
1263 | \*(CD\*(FCclose(\*(FIfile\*(FC)\*(FR
|
---|
1264 | .br
|
---|
1265 | close input or output file, pipe \*(CBor co-process.\*(CD
|
---|
1266 | .ti -.2i
|
---|
1267 | \*(CB\*(FCclose(\*(FIcommand\*(FC, \*(FIhow\*(FC)\*(FR
|
---|
1268 | .br
|
---|
1269 | close one end of co-process pipe.
|
---|
1270 | Use \*(FC"to"\*(FR for the write end, or
|
---|
1271 | \*(FC"from"\*(FR for the read end.\*(CD
|
---|
1272 | .in -.2i
|
---|
1273 | .sp .5
|
---|
1274 | On success, \*(FCclose()\*(FR returns zero for a file, or the exit status for a process.
|
---|
1275 | It returns \-1 if \*(FIfile\*(FR
|
---|
1276 | was never opened, or
|
---|
1277 | if there was a system problem.
|
---|
1278 | \*(CB\*(FCERRNO\*(FR describes
|
---|
1279 | the error.\*(CX
|
---|
1280 | .EB "\s+2\f(HBCLOSING REDIRECTIONS\*(FR\s0"
|
---|
1281 |
|
---|
1282 | .BT
|
---|
1283 |
|
---|
1284 | .\" --- Printf Formats
|
---|
1285 | .ES
|
---|
1286 | .fi
|
---|
1287 | \*(CDThe \*(FCprintf\fP statement and
|
---|
1288 | \*(FCsprintf()\fP function
|
---|
1289 | accept the following conversion specification formats:
|
---|
1290 | .sp .5
|
---|
1291 | .nf
|
---|
1292 | \*(FC%c\fP an \s-1ASCII\s+1 character
|
---|
1293 | \*(FC%d\fP a decimal number (the integer part)
|
---|
1294 | \*(FC%i\fP a decimal number (the integer part)
|
---|
1295 | \*(FC%e\fP a floating point number of the form
|
---|
1296 | \*(FC[\-]d.dddddde[+\^\-]dd\*(FR
|
---|
1297 | \*(FC%E\fP like \*(FC%e\fP, but use \*(FCE\fP instead of \*(FCe\*(FR
|
---|
1298 | \*(FC%f\fP a floating point number of the form
|
---|
1299 | \*(FC[\-]ddd.dddddd\*(FR
|
---|
1300 | \*(FC%g\fP use \*(FC%e\fP or \*(FC%f\fP, whichever is shorter, with
|
---|
1301 | nonsignificant zeros suppressed
|
---|
1302 | \*(FC%G\fP like \*(FC%g\fP, but use \*(FC%E\fP instead of \*(FC%e\*(FR
|
---|
1303 | \*(FC%o\fP an unsigned octal integer
|
---|
1304 | \*(FC%u\fP an unsigned decimal integer
|
---|
1305 | \*(FC%s\fP a character string
|
---|
1306 | \*(FC%x\fP an unsigned hexadecimal integer
|
---|
1307 | \*(FC%X\fP like \*(FC%x\fP, but use \*(FCABCDEF\fP for 10\(en15
|
---|
1308 | \*(FC%%\fP A literal \*(FC%\fP; no argument is converted
|
---|
1309 | .sp .5
|
---|
1310 | .fi
|
---|
1311 | Optional, additional parameters may lie between the \*(FC%\fP
|
---|
1312 | and the control letter:
|
---|
1313 | .sp .5
|
---|
1314 | .TS
|
---|
1315 | expand;
|
---|
1316 | l lw(2.2i).
|
---|
1317 | \*(CB\*(FIcount\*(FC$\*(FR T{
|
---|
1318 | use the
|
---|
1319 | \*(FIcount\*(FR'th
|
---|
1320 | argument at this point in the formatting
|
---|
1321 | (a \*(FIpositional specifier\*(FR).
|
---|
1322 | Use in translated versions of
|
---|
1323 | format strings, not in the original text of an AWK program.\*(CD
|
---|
1324 | T}
|
---|
1325 | \*(FC\-\fP T{
|
---|
1326 | left-justify the expression within its field.
|
---|
1327 | T}
|
---|
1328 | \*(FIspace\fP T{
|
---|
1329 | for numeric conversions, prefix positive values
|
---|
1330 | with a space and negative values with a
|
---|
1331 | minus sign.
|
---|
1332 | T}
|
---|
1333 | \*(FC+\fP T{
|
---|
1334 | used before the \*(FIwidth\fP modifier means to always
|
---|
1335 | supply a sign for numeric conversions, even if
|
---|
1336 | the data to be formatted is positive. The \*(FC+\fP
|
---|
1337 | overrides the space modifier.
|
---|
1338 | T}
|
---|
1339 | \*(FC#\fP T{
|
---|
1340 | use an ``alternate form'' for some control letters.
|
---|
1341 | T}
|
---|
1342 | \*(FC%o\*(FR T{
|
---|
1343 | supply a leading zero.
|
---|
1344 | T}
|
---|
1345 | \*(FC%x\*(FR, \*(FC%X\*(FR T{
|
---|
1346 | supply a leading \*(FC0x\*(FR or \*(FC0X\*(FR for a nonzero result.
|
---|
1347 | T}
|
---|
1348 | \*(FC%e\*(FR, \*(FC%E\*(FR, \*(FC%f\*(FR T{
|
---|
1349 | the result always has a decimal point.
|
---|
1350 | T}
|
---|
1351 | \*(FC%g\*(FR, \*(FC%G\*(FR T{
|
---|
1352 | trailing zeros are not removed.
|
---|
1353 | T}
|
---|
1354 | \*(FC0\fP T{
|
---|
1355 | a leading zero acts as a flag, indicating output
|
---|
1356 | should be padded with zeros instead of spaces.
|
---|
1357 | This applies even to non-numeric output formats.
|
---|
1358 | Only has an effect when the field width is wider
|
---|
1359 | than the value to be printed.
|
---|
1360 | T}
|
---|
1361 | \*(FIwidth\fP T{
|
---|
1362 | pad the field to this width. The field is normally
|
---|
1363 | padded with spaces. If the \*(FC0\fP flag has been used,
|
---|
1364 | pad with zeros.
|
---|
1365 | T}
|
---|
1366 | \*(FC.\*(FIprec\*(FR T{
|
---|
1367 | precision.
|
---|
1368 | The meaning of the \*(FIprec\*(FR varies by control letter:
|
---|
1369 | T}
|
---|
1370 | \*(FC%d\*(FR, \*(FC%o\*(FR, \*(FC%i\*(FR,
|
---|
1371 | \*(FC%u\*(FR, \*(FC%x\*(FR, \*(FC%X\fP T{
|
---|
1372 | the minimum number of digits to print.
|
---|
1373 | T}
|
---|
1374 | \*(FC%e\*(FR, \*(FC%E\*(FR, \*(FC%f\*(FR T{
|
---|
1375 | the number of digits to print to the right of the decimal point.
|
---|
1376 | T}
|
---|
1377 | \*(FC%g\*(FR, \*(FC%G\fP T{
|
---|
1378 | the maximum number of significant digits.
|
---|
1379 | T}
|
---|
1380 | \*(FC%s\fP T{
|
---|
1381 | the maximum number of characters to print.
|
---|
1382 | T}
|
---|
1383 | .TE
|
---|
1384 | .sp .5
|
---|
1385 | .fi
|
---|
1386 | The dynamic \*(FIwidth\fP and \*(FIprec\fP capabilities of the ANSI C
|
---|
1387 | \*(FCprintf()\fP routines are supported.
|
---|
1388 | A \*(FC*\fP in place of either the \*(FIwidth\fP or \*(FIprec\fP
|
---|
1389 | specifications causes their values to be taken from
|
---|
1390 | the argument list to \*(FCprintf\fP or \*(FCsprintf()\*(FR.
|
---|
1391 | \*(CBUse \*(FC*\*(FIn\*(FC$\*(FR to use positional specifiers
|
---|
1392 | with a dynamic width or precision.\*(CX
|
---|
1393 | .EB "\s+2\f(HBPRINTF FORMATS\*(FR\s0"
|
---|
1394 |
|
---|
1395 |
|
---|
1396 | .BT
|
---|
1397 |
|
---|
1398 | .\" --- Special Filenames
|
---|
1399 | .ES
|
---|
1400 | .fi
|
---|
1401 | \*(CDWhen doing I/O redirection from either \*(FCprint\fP
|
---|
1402 | or \*(FCprintf\fP into a file or via \*(FCgetline\fP
|
---|
1403 | from a file, all three implementations of \*(FCawk\fP
|
---|
1404 | recognize certain special filenames internally. These filenames
|
---|
1405 | allow access to open file descriptors inherited from the
|
---|
1406 | parent process (usually the shell).
|
---|
1407 | These filenames may also be used on the command line to name data files.
|
---|
1408 | The filenames are:
|
---|
1409 | .sp .5
|
---|
1410 | .TS
|
---|
1411 | expand;
|
---|
1412 | l lw(2i).
|
---|
1413 | \*(FC"\-"\fP standard input
|
---|
1414 | \*(FC/dev/stdin\fP standard input \*(CR(not \*(MK)\*(CD
|
---|
1415 | \*(FC/dev/stdout\fP standard output
|
---|
1416 | \*(FC/dev/stderr\fP standard error output
|
---|
1417 | .TE
|
---|
1418 | .sp .5
|
---|
1419 | .fi
|
---|
1420 | \*(CBThe following names are specific to \*(GK.
|
---|
1421 | .sp .5
|
---|
1422 | .in +.2i
|
---|
1423 | .ti -.2i
|
---|
1424 | \*(FC/dev/fd/\^\*(FIn\*(FR
|
---|
1425 | .br
|
---|
1426 | File associated with the open file descriptor \*(FIn\*(FR.
|
---|
1427 | .ti -.2i
|
---|
1428 | \*(FC/inet/tcp/\*(FIlport\*(FC/\*(FIrhost\*(FC/\*(FIrport\*(FR
|
---|
1429 | .br
|
---|
1430 | File for TCP/IP connection on local port \*(FIlport\*(FR to
|
---|
1431 | remote host \*(FIrhost\*(FR on remote port \*(FIrport\*(FR.
|
---|
1432 | Use a port of \*(FC0\*(FR to have the system pick a port.
|
---|
1433 | Usable only with the \*(FC|&\*(FR two-way I/O operator.
|
---|
1434 | .ti -.2i
|
---|
1435 | \*(FC/inet/udp/\*(FIlport\*(FC/\*(FIrhost\*(FC/\*(FIrport\*(FR
|
---|
1436 | .br
|
---|
1437 | Similar, but use UDP/IP instead of TCP/IP.
|
---|
1438 | .ti -.2i
|
---|
1439 | \*(CR\*(FC/inet/raw/\*(FIlport\*(FC/\*(FIrhost\*(FC/\*(FIrport\*(FR
|
---|
1440 | .br
|
---|
1441 | .\" Similar, but use raw IP sockets.
|
---|
1442 | Reserved for future use.\*(CB
|
---|
1443 | .in -.2i
|
---|
1444 | .sp .5
|
---|
1445 | .fi
|
---|
1446 | Other special filenames provide access to information about the running
|
---|
1447 | \*(FCgawk\fP process.
|
---|
1448 | Reading from these files returns a single record.
|
---|
1449 | The filenames and what they return are:\*(FR
|
---|
1450 | .sp .5
|
---|
1451 | .TS
|
---|
1452 | expand;
|
---|
1453 | l lw(2i).
|
---|
1454 | \*(FC/dev/pid\fP process ID of current process
|
---|
1455 | \*(FC/dev/ppid\fP parent process ID of current process
|
---|
1456 | \*(FC/dev/pgrpid\fP process group ID of current process
|
---|
1457 | \*(FC/dev/user\fP T{
|
---|
1458 | .nf
|
---|
1459 | a single newline-terminated record.
|
---|
1460 | The fields are separated with spaces.
|
---|
1461 | \*(FC$1\fP is the return value of \*(FIgetuid\*(FR(2),
|
---|
1462 | \*(FC$2\fP is the return value of \*(FIgeteuid\*(FR(2),
|
---|
1463 | \*(FC$3\fP is the return value of \*(FIgetgid\*(FR(2) , and
|
---|
1464 | \*(FC$4\fP is the return value of \*(FIgetegid\*(FR(2).
|
---|
1465 | .fi
|
---|
1466 | Any additional fields are the group IDs returned
|
---|
1467 | by \*(FIgetgroups\*(FR(2). Multiple groups may not be
|
---|
1468 | supported on all systems.
|
---|
1469 | T}
|
---|
1470 | .TE
|
---|
1471 | .sp .5
|
---|
1472 | .fi
|
---|
1473 | \*(CRThese filenames are now obsolete.
|
---|
1474 | Use the \*(FCPROCINFO\fP array to obtain the information they provide.\*(CL
|
---|
1475 | .EB "\s+2\f(HBSPECIAL FILENAMES\*(FR\s0"
|
---|
1476 | .sp .5
|
---|
1477 | .\" --- Builtin Numeric Functions
|
---|
1478 | .ES
|
---|
1479 | .fi
|
---|
1480 | .TS
|
---|
1481 | expand;
|
---|
1482 | l lw(2i).
|
---|
1483 | \*(CD\*(FCatan2(\*(FIy\*(FC, \*(FIx\*(FC)\*(FR the arctangent of \*(FIy/x\fP in radians.
|
---|
1484 | \*(FCcos(\*(FIexpr\*(FC)\*(FR the cosine of \*(FIexpr\fP, which is in radians.
|
---|
1485 | \*(FCexp(\*(FIexpr\*(FC)\*(FR the exponential function (\*(FIe \*(FC^ \*(FIx\*(FR).
|
---|
1486 | \*(FCint(\*(FIexpr\*(FC)\*(FR truncates to integer.
|
---|
1487 | \*(FClog(\*(FIexpr\*(FC)\*(FR the natural logarithm function (base \*(FIe\^\*(FR).
|
---|
1488 | \*(FCrand()\fP a random number between 0 and 1 (0 \(<= \*(FIN\fP < 1).
|
---|
1489 | \*(FCsin(\*(FIexpr\*(FC)\*(FR the sine of \*(FIexpr\fP, which is in radians.
|
---|
1490 | \*(FCsqrt(\*(FIexpr\*(FC)\*(FR the square root function.
|
---|
1491 | \&\*(FCsrand(\*(FR[\*(FIexpr\^\*(FR]\*(FC)\*(FR T{
|
---|
1492 | uses \*(FIexpr\fP as a new seed for the random number
|
---|
1493 | generator. If no \*(FIexpr\fP, the time of day is used.
|
---|
1494 | Returns previous seed for the random number
|
---|
1495 | generator.\*(CX
|
---|
1496 | T}
|
---|
1497 | .TE
|
---|
1498 | .EB "\s+2\f(HBNUMERIC FUNCTIONS\*(FR\s0"
|
---|
1499 | .sp .5
|
---|
1500 | .\" --- Extensions
|
---|
1501 | .ES
|
---|
1502 | .fi
|
---|
1503 | .in +.2i
|
---|
1504 | .ti -.2i
|
---|
1505 | \*(CD\*(FCextension(\*(FIlib\*(FC, \*(FIfunc\*(FC)\*(FR
|
---|
1506 | .br
|
---|
1507 | dynamically load the shared library
|
---|
1508 | \*(FIlib\*(FR
|
---|
1509 | and call
|
---|
1510 | \*(FIfunc\*(FR
|
---|
1511 | in it to initialize the library.
|
---|
1512 | This adds new built-in functions to \*(GK.
|
---|
1513 | It returns the value returned by
|
---|
1514 | \*(FIfunc\*(FR.\*(CB
|
---|
1515 | .in -.2i
|
---|
1516 | .EB "\s+2\f(HBDYNAMIC EXTENSIONS (\*(GK\f(HB)\*(FR\s0"
|
---|
1517 |
|
---|
1518 |
|
---|
1519 | .BT
|
---|
1520 |
|
---|
1521 | .\" --- Builtin String Functions
|
---|
1522 | .ES
|
---|
1523 | .fi
|
---|
1524 | .in +.2i
|
---|
1525 | .ti -.2i
|
---|
1526 | \*(CB\*(FCasort(\*(FIs\*(FC \*(FR[\*(FC, \*(FId\*(FR]\*(FC)\*(FR
|
---|
1527 | .br
|
---|
1528 | sorts the source array \*(FIs\*(FR, replacing the indices with numeric
|
---|
1529 | values 1 through \*(FIn\*(FR (the number of elements in the array),
|
---|
1530 | and returns the number of elements.
|
---|
1531 | If destination \*(FId\*(FR is supplied, \*(FIs\*(FR is copied to \*(FId\*(FR,
|
---|
1532 | \*(FId\*(FR is sorted, and \*(FIs\*(FR is unchanged.\*(CD
|
---|
1533 | .ti -.2i
|
---|
1534 | \*(CB\*(FCasorti(\*(FIs\*(FC \*(FR[\*(FC, \*(FId\*(FR]\*(FC)\*(FR
|
---|
1535 | .br
|
---|
1536 | like \*(FCasort()\*(FR, but sorting is done on the indices, not
|
---|
1537 | the values. The original values are thrown array, so provide a
|
---|
1538 | second array to preserve the first.\*(CD
|
---|
1539 | .ti -.2i
|
---|
1540 | \*(CB\*(FCgensub(\*(FIr\*(FC, \*(FIs\*(FC, \*(FIh \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
---|
1541 | .br
|
---|
1542 | search the target string
|
---|
1543 | \*(FIt\fP for matches of the regular expression \*(FIr\*(FR. If
|
---|
1544 | \*(FIh\fP is a string beginning with \*(FCg\fP or \*(FCG\*(FR,
|
---|
1545 | replace all matches of \*(FIr\fP with \*(FIs\*(FR. Otherwise, \*(FIh\fP
|
---|
1546 | is a number indicating which match of \*(FIr\fP to replace.
|
---|
1547 | If \*(FIt\fP is not supplied, \*(FC$0\fP is used instead. Within the
|
---|
1548 | replacement text \*(FIs\*(FR, the sequence \*(FC\e\*(FIn\*(FR,
|
---|
1549 | where \*(FIn\fP is a digit from 1 to 9, may be used to indicate just
|
---|
1550 | the text that matched the \*(FIn\*(FRth parenthesized subexpression.
|
---|
1551 | The sequence \*(FC\e0\fP represents the entire matched text, as does
|
---|
1552 | the character \*(FC&\*(FR. Unlike \*(FCsub()\fP and \*(FCgsub()\*(FR,
|
---|
1553 | the modified string is returned as the result of the function,
|
---|
1554 | and the original target string is \*(FInot\fP changed.\*(CD
|
---|
1555 | .ti -.2i
|
---|
1556 | \*(FCgsub(\*(FIr\*(FC, \*(FIs \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
---|
1557 | .br
|
---|
1558 | for each substring matching the
|
---|
1559 | regular expression \*(FIr\fP in the string \*(FIt\*(FR, substitute the
|
---|
1560 | string \*(FIs\*(FR, and return the number of substitutions. If
|
---|
1561 | \*(FIt\fP is not supplied, use \*(FC$0\*(FR. An \*(FC&\fP in the
|
---|
1562 | replacement text is replaced with the text that was actually matched.
|
---|
1563 | Use \*(FC\e&\fP to get a literal \*(FC&\*(FR. See \*(AM
|
---|
1564 | for a fuller discussion of the rules for \*(FC&\*(FR's and backslashes
|
---|
1565 | in the replacement text of \*(CB\*(FCgensub()\*(FR,\*(CD \*(FCsub()\*(FR
|
---|
1566 | and \*(FCgsub()\*(FR
|
---|
1567 | .ti -.2i
|
---|
1568 | \*(FCindex(\*(FIs\*(FC, \*(FIt\*(FC)\*(FR
|
---|
1569 | .br
|
---|
1570 | returns the index of the string
|
---|
1571 | \*(FIt\fP in the string \*(FIs\*(FR, or 0 if \*(FIt\fP is not present.
|
---|
1572 | .ti -.2i
|
---|
1573 | \*(FClength(\*(FR[\*(FIs\*(FR]\*(FC)\*(FR
|
---|
1574 | .br
|
---|
1575 | returns the length of the string
|
---|
1576 | \*(FIs\*(FR, or the length of \*(FC$0\fP if \*(FIs\fP is not supplied.
|
---|
1577 | \*(CBWith an array argument, returns the number of elements
|
---|
1578 | in the array.\*(CD
|
---|
1579 | .ti -.2i
|
---|
1580 | \*(FCmatch(\*(FIs\*(FC, \*(FIr \*(CB\*(FR[\*(FC, \*(FIa\*(FR]\*(CD\*(FC)\*(FR
|
---|
1581 | .br
|
---|
1582 | returns the position in
|
---|
1583 | \*(FIs\fP where the regular expression \*(FIr\fP occurs, or 0 if
|
---|
1584 | \*(FIr\fP is not present, and sets the values of variables
|
---|
1585 | \*(FCRSTART\fP
|
---|
1586 | and \*(FCRLENGTH\*(FR.
|
---|
1587 | \*(CBIf \*(FIa\*(FR is supplied, the text matching all of \*(FIr\*(FR
|
---|
1588 | is placed in \*(FIa\*(FC[0]\*(FR. If there were parenthesized
|
---|
1589 | subexpressions, the matching texts are placed
|
---|
1590 | in \*(FIa\*(FC[1]\*(FR, \*(FIa\*(FC[2]\*(FR, and so on.
|
---|
1591 | Subscripts
|
---|
1592 | \*(FCa[\*(FIn\^\*(FC, "start"]\*(FR,
|
---|
1593 | and
|
---|
1594 | \*(FCa[\*(FIn\^\*(FC, "length"]\*(FR
|
---|
1595 | provide the starting index in the string and length
|
---|
1596 | respectively, of each matching substring.\*(CD
|
---|
1597 | .ti -.2i
|
---|
1598 | \*(FCsplit(\*(FIs\*(FC, \*(FIa \*(FR[\*(FC, \*(FIr\*(FR]\*(FC)\*(FR
|
---|
1599 | .br
|
---|
1600 | splits the string
|
---|
1601 | \*(FIs\fP into the array \*(FIa\fP using the regular expression \*(FIr\*(FR,
|
---|
1602 | and returns the number of fields. If \*(FIr\fP is omitted, \*(FCFS\fP
|
---|
1603 | is used instead. The array \*(FIa\fP is cleared first.
|
---|
1604 | Splitting behaves identically to field splitting.
|
---|
1605 | (See \fHFields\fP, above.)
|
---|
1606 | .ti -.2i
|
---|
1607 | \*(FCsprintf(\*(FIfmt\*(FC, \*(FIexpr-list\*(FC)\*(FR
|
---|
1608 | .br
|
---|
1609 | prints \*(FIexpr-list\fP
|
---|
1610 | according to \*(FIfmt\*(FR, and returns the resulting string.
|
---|
1611 | .ti -.2i
|
---|
1612 | \*(CB\*(FCstrtonum(\*(FIs\*(FC)\*(FR
|
---|
1613 | .br
|
---|
1614 | examines \*(FIs\*(FR, and returns its numeric value.
|
---|
1615 | If \*(FIs\*(FR begins with a leading \*(FC0\*(FR,
|
---|
1616 | \*(FCstrtonum()\*(FR assumes that \*(FIs\*(FR
|
---|
1617 | is an octal number.
|
---|
1618 | If \*(FIs\*(FR begins with a leading \*(FC0x\*(FR
|
---|
1619 | or \*(FC0X\*(FR, \*(FCstrtonum()\*(FR assumes that
|
---|
1620 | \*(FIs\*(FR is a hexadecimal number.\*(CD
|
---|
1621 | .ti -.2i
|
---|
1622 | \*(FCsub(\*(FIr\*(FC, \*(FIs \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
---|
1623 | .br
|
---|
1624 | just like
|
---|
1625 | \*(FCgsub()\*(FR, but only the first matching substring is replaced.\*(CX
|
---|
1626 | .in -.2i
|
---|
1627 | .EB "\s+2\f(HBSTRING FUNCTIONS\*(FR\s0"
|
---|
1628 |
|
---|
1629 | .BT
|
---|
1630 |
|
---|
1631 | .\" --- Builtin String Functions
|
---|
1632 | .ES
|
---|
1633 | .fi
|
---|
1634 | .in +.2i
|
---|
1635 | .ti -.2i
|
---|
1636 | \*(CD\*(FCsubstr(\*(FIs\*(FC, \*(FIi \*(FR[\*(FC, \*(FIn\*(FR]\*(FC)\*(FR
|
---|
1637 | .br
|
---|
1638 | returns the at most
|
---|
1639 | \*(FIn\*(FR-character substring of \*(FIs\fP starting at \*(FIi\*(FR.
|
---|
1640 | If \*(FIn\fP is omitted, the rest of \*(FIs\fP is used.
|
---|
1641 | .ti -.2i
|
---|
1642 | \*(FCtolower(\*(FIstr\*(FC)\*(FR
|
---|
1643 | .br
|
---|
1644 | returns a copy of the string \*(FIstr\*(FR,
|
---|
1645 | with all the upper-case characters in \*(FIstr\fP translated to their
|
---|
1646 | corresponding lower-case counterparts. Non-alphabetic characters are
|
---|
1647 | left unchanged.
|
---|
1648 | .ti -.2i
|
---|
1649 | \*(FCtoupper(\*(FIstr\*(FC)\*(FR
|
---|
1650 | .br
|
---|
1651 | returns a copy of the string \*(FIstr\*(FR,
|
---|
1652 | with all the lower-case characters in \*(FIstr\fP translated to their
|
---|
1653 | corresponding upper-case counterparts. Non-alphabetic characters are
|
---|
1654 | left unchanged.\*(CX
|
---|
1655 | .in -.2i
|
---|
1656 | .EB "\s+2\f(HBSTRING FUNCTIONS (continued)\*(FR\s0"
|
---|
1657 |
|
---|
1658 | .\" --- Builtin Time Functions
|
---|
1659 | .ES
|
---|
1660 | .fi
|
---|
1661 | \*(CD\*(GK
|
---|
1662 | provides the following functions for obtaining time stamps and
|
---|
1663 | formatting them.
|
---|
1664 | .sp .5
|
---|
1665 | .fi
|
---|
1666 | .in +.2i
|
---|
1667 | .ti -.2i
|
---|
1668 | \*(FCmktime(\*(FIdatespec\*(FC)\*(FR
|
---|
1669 | .br
|
---|
1670 | turns \*(FIdatespec\fP into a time
|
---|
1671 | stamp of the same form as returned by \*(FCsystime()\*(FR.
|
---|
1672 | The \*(FIdatespec\fP is a string of the form
|
---|
1673 | \*(FC"\*(FIYYYY MM DD HH MM SS[ DST]\*(FC"\*(FR.
|
---|
1674 | .ti -.2i
|
---|
1675 | \*(FCstrftime(\*(FR[\*(FIformat \*(FR[\*(FC, \*(FItimestamp\*(FR]]\*(FC)\*(FR
|
---|
1676 | .br
|
---|
1677 | formats \*(FItimestamp\fP
|
---|
1678 | according to the specification in \*(FIformat\*(FR. The
|
---|
1679 | \*(FItimestamp\fP should be of the same form as returned by
|
---|
1680 | \*(FCsystime()\*(FR.
|
---|
1681 | If \*(FItimestamp\fP is missing, the current time of day is used. If
|
---|
1682 | \*(FIformat\fP is missing, a default format equivalent to the output
|
---|
1683 | of \*(FIdate\*(FR(1) is used.
|
---|
1684 | .ti -.2i
|
---|
1685 | \*(FCsystime()\fP
|
---|
1686 | .br
|
---|
1687 | returns the current time of day as the number of
|
---|
1688 | seconds since the Epoch.\*(CB
|
---|
1689 | .in -.2i
|
---|
1690 | .EB "\s+2\f(HBTIME FUNCTIONS (\*(GK\f(HB)\*(FR\s0"
|
---|
1691 |
|
---|
1692 | .\" --- Builtin Bit Manipulation Functions
|
---|
1693 | .ES
|
---|
1694 | .fi
|
---|
1695 | \*(CD\*(GK
|
---|
1696 | provides the following functions for doing bitwise operations.
|
---|
1697 | .sp .5
|
---|
1698 | .fi
|
---|
1699 | .in +.2i
|
---|
1700 | .ti -.2i
|
---|
1701 | \*(FCand(\*(FIv1\*(FC, \*(FIv2\*(FC)\*(FR
|
---|
1702 | .br
|
---|
1703 | returns the bitwise AND of the values provided by
|
---|
1704 | \*(FIv1\*(FR and \*(FIv2\*(FR.
|
---|
1705 | .ti -.2i
|
---|
1706 | \*(FCcompl(\*(FIval\*(FC)\*(FR
|
---|
1707 | .br
|
---|
1708 | returns the bitwise complement of
|
---|
1709 | \*(FIval\*(FR.
|
---|
1710 | .ti -.2i
|
---|
1711 | \*(FClshift(\*(FIval\*(FC, \*(FIcount\*(FC)\*(FR
|
---|
1712 | .br
|
---|
1713 | returns the value of \*(FIval\*(FR,
|
---|
1714 | shifted left by \*(FIcount\*(FR bits.
|
---|
1715 | .ti -.2i
|
---|
1716 | \*(FCor(\*(FIv1\*(FC, \*(FIv2\*(FC)\*(FR
|
---|
1717 | .br
|
---|
1718 | returns the bitwise OR of the values provided by
|
---|
1719 | \*(FIv1\*(FR and \*(FIv2\*(FR.
|
---|
1720 | .ti -.2i
|
---|
1721 | \*(FCrshift(\*(FIval\*(FC, \*(FIcount\*(FC)\*(FR
|
---|
1722 | .br
|
---|
1723 | returns the value of \*(FIval\*(FR,
|
---|
1724 | shifted right by \*(FIcount\*(FR bits.
|
---|
1725 | .ti -.2i
|
---|
1726 | \*(FCxor(\*(FIv1\*(FC, \*(FIv2\*(FC)\*(FR
|
---|
1727 | .br
|
---|
1728 | teturns the bitwise XOR of the values provided by
|
---|
1729 | \*(FIv1\*(FR and \*(FIv2\*(FR.\*(CB
|
---|
1730 | .in -.2i
|
---|
1731 | .EB "\s+2\f(HBBIT MANIPULATION FUNCTIONS (\*(GK\f(HB)\*(FR\s0"
|
---|
1732 |
|
---|
1733 | .\" --- Environment Variables
|
---|
1734 | .ES
|
---|
1735 | .fi
|
---|
1736 | \*(CDThe environment variable \*(FCAWKPATH\fP specifies a search path to use
|
---|
1737 | when finding source files named with the \*(FC\-f\fP
|
---|
1738 | option.
|
---|
1739 | The default path is
|
---|
1740 | \*(FC".:/usr/local/share/awk"\*(FR.
|
---|
1741 | .\" if this variable does not exist.
|
---|
1742 | .\" (The actual directory may vary,
|
---|
1743 | .\" depending upon how \*(GK was built and installed.)
|
---|
1744 | If a file name given to the \*(FC\-f\fP option contains a ``/'' character,
|
---|
1745 | no path search is performed.
|
---|
1746 | .sp .5
|
---|
1747 | If \*(FCPOSIXLY_CORRECT\fP exists
|
---|
1748 | .\" in the environment,
|
---|
1749 | then \*(GK
|
---|
1750 | behaves exactly as if the \*(FC\-\^\-posix\fP option had been given.\*(CB
|
---|
1751 | .EB "\s+2\f(HBENVIRONMENT VARIABLES (\*(GK\f(HB)\*(FR\s0"
|
---|
1752 |
|
---|
1753 | .BT
|
---|
1754 |
|
---|
1755 | .\" --- User-defined Functions
|
---|
1756 | .ES
|
---|
1757 | .fi
|
---|
1758 | \*(CDFunctions in AWK are defined as follows:
|
---|
1759 | .sp .5
|
---|
1760 | .nf
|
---|
1761 | \*(FCfunction \*(FIname\*(FC(\*(FIparameter list\*(FC)
|
---|
1762 | {
|
---|
1763 | \*(FIstatements
|
---|
1764 | \*(FC}\*(FR
|
---|
1765 | .sp .5
|
---|
1766 | .fi
|
---|
1767 | Functions are executed when they are called from within expressions
|
---|
1768 | in either patterns or actions. Actual parameters supplied in the function
|
---|
1769 | call instantiate the formal parameters declared in the function.
|
---|
1770 | Arrays are passed by reference, other variables are passed by value.
|
---|
1771 | .sp .5
|
---|
1772 | Local variables are declared as extra parameters
|
---|
1773 | in the parameter list. The convention is to separate local variables from
|
---|
1774 | real parameters by extra spaces in the parameter list. For example:
|
---|
1775 | .sp .5
|
---|
1776 | .nf
|
---|
1777 | \*(FC# a and b are local
|
---|
1778 | function f(p, q, a, b)
|
---|
1779 | {
|
---|
1780 | \&.....
|
---|
1781 | }
|
---|
1782 | .sp .3
|
---|
1783 | /abc/ { ... ; f(1, 2) ; ... }\*(FR
|
---|
1784 | .fi
|
---|
1785 | .sp .5
|
---|
1786 | The left parenthesis in a function call is required
|
---|
1787 | to immediately follow the function name
|
---|
1788 | without any intervening white space.
|
---|
1789 | This is to avoid a syntactic ambiguity with the concatenation operator.
|
---|
1790 | This restriction does not apply to the built-in functions.
|
---|
1791 | .sp .5
|
---|
1792 | Functions may call each other and may be recursive.
|
---|
1793 | Function parameters used as local variables are initialized
|
---|
1794 | to the null string and the number zero upon function invocation.
|
---|
1795 | .sp .5
|
---|
1796 | Use \*(FCreturn\fP to return a value from a function. The return value
|
---|
1797 | is undefined if no value is provided, or if the function returns by
|
---|
1798 | ``falling off'' the end.
|
---|
1799 | .sp .5
|
---|
1800 | \*(CLThe word
|
---|
1801 | \*(FCfunc\fP
|
---|
1802 | may be used in place of
|
---|
1803 | \*(FCfunction\*(FR.
|
---|
1804 | \*(CRNote: This usage is deprecated.\*(CX
|
---|
1805 | .EB "\s+2\f(HBUSER-DEFINED FUNCTIONS\*(FR\s0"
|
---|
1806 |
|
---|
1807 | .\" --- Localization
|
---|
1808 | .ES
|
---|
1809 | .fi
|
---|
1810 | \*(CDThere are several steps involved in producing and running a localizable
|
---|
1811 | \*(AK program.
|
---|
1812 | .sp .5
|
---|
1813 | 1. Add a \*(FCBEGIN\*(FR action to assign a value to the
|
---|
1814 | \*(FCTEXTDOMAIN\*(FR variable to set the text domain for
|
---|
1815 | your program.
|
---|
1816 | .sp .5
|
---|
1817 | .ti +5n
|
---|
1818 | \*(FCBEGIN { TEXTDOMAIN = "myprog" }\*(FR
|
---|
1819 | .sp .5
|
---|
1820 | This allows \*(GK to find the \*(FC\&.mo\*(FR
|
---|
1821 | file associated with your program.
|
---|
1822 | Without this step, \*(GK uses the \*(FCmessages\*(FR text domain,
|
---|
1823 | which probably won't work.
|
---|
1824 | .sp .5
|
---|
1825 | 2. Mark all strings that should be translated with leading underscores.
|
---|
1826 | .sp .5
|
---|
1827 | 3. Use the
|
---|
1828 | \*(FCbindtextdomain()\*(FR,
|
---|
1829 | \*(FCdcgettext()\*(FR,
|
---|
1830 | and/or
|
---|
1831 | \*(FCdcngettext()\*(FR
|
---|
1832 | functions in your program, as appropriate.
|
---|
1833 | .sp .5
|
---|
1834 | 4. Run
|
---|
1835 | .sp .5
|
---|
1836 | .ti +5n
|
---|
1837 | \*(FCgawk \-\^\-gen\-po \-f myprog.awk > myprog.po\*(FR
|
---|
1838 | .sp .5
|
---|
1839 | to generate a \*(FC\&.po\*(FR
|
---|
1840 | file for your program.
|
---|
1841 | .sp .5
|
---|
1842 | 5. Provide appropriate translations, and build and install a corresponding
|
---|
1843 | \*(FC\&.mo\*(FR file.
|
---|
1844 | .sp .5
|
---|
1845 | The internationalization features are described in full detail in \*(AM.\*(CB
|
---|
1846 | .EB "\s+2\f(HBLOCALIZATION (\*(GK\f(HB)\*(FR\s0"
|
---|
1847 |
|
---|
1848 |
|
---|
1849 | .BT
|
---|
1850 |
|
---|
1851 | .\" --- Builtin Internationalization Functions
|
---|
1852 | .ES
|
---|
1853 | .fi
|
---|
1854 | \*(CD\*(GK
|
---|
1855 | provides the following functions for runtime message translation.
|
---|
1856 | .in +.2i
|
---|
1857 | .sp .5
|
---|
1858 | .ti -.2i
|
---|
1859 | \*(FCbindtextdomain(\*(FIdirectory \*(FR[\*(FC, \*(FIdomain\*(FR]\*(FC)\*(FR
|
---|
1860 | .br
|
---|
1861 | specifies the directory where \*(GK looks for the \*(FC\&.mo\*(FR
|
---|
1862 | files, in case they
|
---|
1863 | will not or cannot be placed in the ``standard'' locations
|
---|
1864 | (e.g., during testing.)
|
---|
1865 | It returns the directory where \*(FIdomain\*(FR is ``bound.''
|
---|
1866 | .sp .5
|
---|
1867 | The default \*(FIdomain\*(FR is the value of \*(FCTEXTDOMAIN\*(FR.
|
---|
1868 | When \*(FIdirectory\*(FR is the null string (\*(FC"\^"\*(FR),
|
---|
1869 | \*(FCbindtextdomain()\*(FR returns the current binding for the
|
---|
1870 | given \*(FIdomain\*(FR.
|
---|
1871 | .ti -.2i
|
---|
1872 | \*(FCdcgettext(\*(FIstring \*(FR[\*(FC, \*(FIdomain \*(FR[\*(FC, \*(FIcategory\*(FR]]\*(FC)\*(FR
|
---|
1873 | .br
|
---|
1874 | returns the translation of \*(FIstring\*(FR in text domain
|
---|
1875 | \*(FIdomain\*(FR for locale category \*(FIcategory\*(FR.
|
---|
1876 | The default value for \*(FIdomain\*(FR is the current value of \*(FCTEXTDOMAIN\*(FR.
|
---|
1877 | The default value for \*(FIcategory\*(FR is \*(FC"LC_MESSAGES"\*(FR.
|
---|
1878 | .sp .5
|
---|
1879 | If you supply a value for \*(FIcategory\*(FR, it must be a string equal to
|
---|
1880 | one of the known locale categories.
|
---|
1881 | You must also supply a text domain. Use \*(FCTEXTDOMAIN\*(FR
|
---|
1882 | to use the current domain.
|
---|
1883 | .ti -.2i
|
---|
1884 | \*(FCdcngettext(\*(FIstring1\*(FC, \*(FIstring2\*(FC, \*(FInumber\*(FR [\*(FC, \*(FIdom \*(FR[\*(FC, \*(FIcat\*(FR]]\*(FC)\*(FR
|
---|
1885 | .br
|
---|
1886 | returns the plural form used for \*(FInumber\*(FR of the translation of
|
---|
1887 | \*(FIstring1\*(FR and \*(FIstring2\*(FR in text domain
|
---|
1888 | \*(FIdom\*(FR for locale category \*(FIcat\*(FR.
|
---|
1889 | The default value for \*(FIdom\*(FR is the current value of \*(FCTEXTDOMAIN\*(FR.
|
---|
1890 | \*(FC"LC_MESSAGES"\*(FR
|
---|
1891 | is the default value for \*(FIcat\*(FR.
|
---|
1892 | .sp .5
|
---|
1893 | If you supply a value for \*(FIcat\*(FR, it must be a string equal to
|
---|
1894 | one of the known locale categories.
|
---|
1895 | You must also supply a text domain. Use \*(FCTEXTDOMAIN\*(FR
|
---|
1896 | to use the current domain.\*(CB
|
---|
1897 | .in -.2i
|
---|
1898 | .EB "\s+2\f(HBINTERNATIONALIZATION (\*(GK\f(HB)\*(FR\s0"
|
---|
1899 |
|
---|
1900 |
|
---|
1901 | .\" --- FTP/HTTP Information
|
---|
1902 | .ES
|
---|
1903 | .nf
|
---|
1904 | \*(CDHost: \*(FCftp.gnu.org\*(FR
|
---|
1905 | File: \*(FC/gnu/gawk/gawk-3.1.5.tar.gz\fP
|
---|
1906 | .in +.2i
|
---|
1907 | .fi
|
---|
1908 | GNU \*(AK (\*(GK). There may be a later version.
|
---|
1909 | .in -.2i
|
---|
1910 | .nf
|
---|
1911 | .sp .5
|
---|
1912 | \*(FChttp://cm.bell-labs.com/who/bwk/awk.tar.gz\fP
|
---|
1913 | .in +.2i
|
---|
1914 | .fi
|
---|
1915 | \*(NK. This version requires an ANSI C compiler;
|
---|
1916 | GCC (the GNU Compiler Collection) works well.
|
---|
1917 | .in -.2i
|
---|
1918 | .nf
|
---|
1919 | .sp .5
|
---|
1920 | Host: \*(FCftp.whidbey.net\*(FR
|
---|
1921 | File: \*(FC/pub/brennan/mawk1.3.3.tar.gz\fP
|
---|
1922 | .in +.2i
|
---|
1923 | .fi
|
---|
1924 | Michael Brennan's \*(MK. There may be a newer version.\*(CX
|
---|
1925 | .in -.2i
|
---|
1926 | .EB "\s+2\f(HBFTP/HTTP INFORMATION\*(FR\s0"
|
---|
1927 |
|
---|
1928 |
|
---|
1929 | .\" --- Copying Permissions
|
---|
1930 | .ES
|
---|
1931 | .fi
|
---|
1932 | \*(CDCopyright \(co 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
|
---|
1933 | Free Software Foundation, Inc.
|
---|
1934 | .sp .5
|
---|
1935 | Permission is granted to make and distribute verbatim copies of this
|
---|
1936 | reference card provided the copyright notice and this permission notice
|
---|
1937 | are preserved on all copies.
|
---|
1938 | .sp .5
|
---|
1939 | Permission is granted to copy and distribute modified versions of this
|
---|
1940 | reference card under the conditions for verbatim copying, provided that
|
---|
1941 | the entire resulting derived work is distributed under the terms of a
|
---|
1942 | permission notice identical to this one.
|
---|
1943 | .sp .5
|
---|
1944 | Permission is granted to copy and distribute translations of this
|
---|
1945 | reference card into another language, under the above conditions for
|
---|
1946 | modified versions, except that this permission notice may be stated in a
|
---|
1947 | translation approved by the Foundation.\*(CX
|
---|
1948 | .EB "\s+2\f(HBCOPYING PERMISSIONS\*(FR\s0"
|
---|
1949 | .BT
|
---|