source: vendor/bash/3.1-p17/tests/cond.tests

#
# the test/[ code is tested elsewhere, and the [[...]] just uses the same
# code.  this tests the special features of [[...]]
#
TDIR=/usr/homes/chet

# this one is straight out of the ksh88 book
[[ foo > bar && $PWD -ef . ]]
echo returns: $?

# [[ x ]] is equivalent to [[ -n x ]]
[[ x ]]
echo returns: $?

# [[ ! x ]] is equivalent to [[ ! -n x ]]
[[ ! x ]]
echo returns: $?

# ! binds tighter than test/[ -- it binds to a term, not an expression
[[ ! x || x ]]
echo returns: $?

# parenthesized terms didn't work right until post-2.04
[[ a ]]
echo returns: $?

[[ (a) ]]
echo returns: $?

[[ -n a ]]
echo returns: $?

[[ (-n a) ]]
echo returns: $?

# unset variables don't need to be quoted
[[ -n $UNSET ]]
echo returns: $?

[[ -z $UNSET ]]
echo returns: $?

# the ==/= and != operators do pattern matching
[[ $TDIR == /usr/homes/* ]]
echo returns: $?

# ...but you can quote any part of the pattern to have it matched as a string
[[ $TDIR == /usr/homes/\* ]]
echo returns: $?

[[ $TDIR == '/usr/homes/*' ]]
echo returns: $?

# if the first part of && fails, the second is not executed
[[ -n $UNSET && $UNSET == foo ]]
echo returns: $?

[[ -z $UNSET && $UNSET == foo ]]
echo returns: $?

# if the first part of || succeeds, the second is not executed
[[ -z $UNSET || -d $PWD ]]
echo returns: $?

# if the rhs were executed, it would be an error
[[ -n $TDIR || $HOME -ef ${H*} ]]
echo returns: $?

[[ -n $TDIR && -z $UNSET || $HOME -ef ${H*} ]]
echo returns: $?

# && has a higher parsing precedence than ||
[[ -n $TDIR && -n $UNSET || $TDIR -ef . ]]
echo returns: $?

# ...but expressions in parentheses may be used to override precedence rules
[[ -n $TDIR || -n $UNSET && $PWD -ef xyz ]]
echo returns: $?

[[ ( -n $TDIR || -n $UNSET ) && $PWD -ef xyz ]]
echo returns: $?

# some arithmetic tests for completeness -- see what happens with missing
# operands, bad expressions, makes sure arguments are evaluated as
# arithmetic expressions, etc.

unset IVAR A
[[ 7 -gt $IVAR ]]
echo returns: $?

[[ $IVAR -gt 7 ]]
echo returns: $?

IVAR=4
[[ $IVAR -gt 7 ]]
echo returns: $?

[[ 7 -eq 4+3 ]]
echo returns: $?

[[ 7 -eq 4+ ]] 
echo returns: $? 

IVAR=4+3
[[ $IVAR -eq 7 ]]
echo returns: $?

A=7
[[ $IVAR -eq A ]]
echo returns: $?

unset IVAR A

# more pattern matching tests

[[ $filename == *.c ]]
echo returns: $?

filename=patmatch.c

[[ $filename == *.c ]]
echo returns: $?

# the extended globbing features may be used when matching patterns
shopt -s extglob

arg=-7

[[ $arg == -+([0-9]) ]]
echo returns: $?

arg=-H

[[ $arg == -+([0-9]) ]]
echo returns: $?

arg=+4
[[ $arg == ++([0-9]) ]]
echo returns: $?

# make sure the null string is never matched if the string is not null
STR=file.c
PAT=

if [[ $STR = $PAT ]]; then
        echo oops
fi

# but that if the string is null, a null pattern is matched correctly
STR=
PAT=

if [[ $STR = $PAT ]]; then
        echo ok
fi

# bug in all versions up to and including bash-2.05b
if [[ "123abc" == *?(a)bc ]]; then echo ok 42; else echo bad 42; fi
if [[ "123abc" == *?(a)bc ]]; then echo ok 43; else echo bad 43; fi