source: trunk/essentials/net-misc/wget/INSTALL@ 3453

                                                            -*- text -*-
                   GNU Wget Installation Procedure
                   ===============================

0. Introduction
---------------

This document describes how to build Wget from source code on
Unix-like systems.  If you want to install a precompiled Wget, this
document is not for you -- refer to the documentation provided by the
distributors instead.  If you already have Wget and want to learn how
to use it, refer to Wget's Info documentation or man page which you
should have received with your system.  If you are using Windows
(except for Cygwin), read windows/README instead.  If you want to
compile Wget from source code on a Unix-like system, read on.

The preferred form of building Wget is to get a release archive and
unpack it (which you have presumably done, since you are reading
this).  If you have obtained the source code via the Subversion
repository, please follow the instructions in `README.checkout' before
continuing.

1. Dependencies
---------------

To build Wget, your system must support a Unix-like command-line
development environment, including the text-processing utilities (sh,
grep, awk, sed, etc.) and a functional C compiler.  On some GNU/Linux
systems, this means that you will need to install packages such as
`gcc', `glibc-devel' (or `libc6-dev') and `make'.  Most systems come
with these packages preinstalled, but it doesn't hurt to check.  If
you have successfully compiled other software from source, you
probably have them all.

In addition to the C development environment, Wget can use a number of
optional libraries to provide additional features, such as translated
messages and support for "https" URLs.  The "external" dependencies
include:

  - OpenSSL -- for "https" URLs.
  - GNU gettext -- for translated messages.

To be usable for building Wget, the listed libraries must be installed
with their "development" header files.  On GNU/Linux systems this
typically means installing the corredponsing "lib<name>-devel" or
"lib<name>-dev" package along with the package with "lib<name>".

2. Configuration
----------------

Before compiling Wget, you need to "configure" it using the
`configure' script provided with the distribution.  Configuration
serves two distinct purposes: it enables Wget's build system to
inspect certain features of your operating system for more robust
compilation, and it enables you to choose which features you want the
resulting Wget to have.

As is the case with most GNU software, Wget's configure script was
generated with GNU Autoconf.  If you're not familiar with
Autoconf-generated scripts, read on.

The most straightforward way to configure Wget is by running the
configure script without any arguments.  After running some
compilation-related tests, it will create the Makefiles needed to
build Wget.  However, you may wish to customize Wget's configuration
by providing arguments to `configure'.  Wget's configure script
accepts standard Autoconf arguments, the most important ones being:

  --help                  display a help message and exit

  --prefix=PREFIX         install architecture-independent files in PREFIX
                          (/usr/local by default)
  --bindir=DIR            user executables in DIR (PREFIX/bin)
  --infodir=DIR           info documentation in DIR [PREFIX/info]
  --mandir=DIR            man documentation in DIR [PREFIX/man]

For example, if you are not root and want to install Wget in
subdirectories of your home directory, you can use:

    ./configure --prefix=$HOME

In addition to the above generic options, Wget's configuration
supports a number of options more or less specific to Wget.  Options
beginning with "--disable", such as `--disable-opie' or
`--disable-ntlm', allow you to turn off certain built-in functionality
you don't need in order to reduce the size of the executable.  Options
beginning with "--with" turning off autodetection and use of external
software Wget can link with, such as the SSL libraries.  Recognized
"--enable" and "--with" options include:

  --without-ssl           disable SSL autodetection (used for https support)
  --with-libssl-prefix=DIR search for libssl in DIR/lib
  --disable-opie          disable support for opie or s/key FTP login
  --disable-digest        disable support for HTTP digest authorization
  --disable-ntlm          disable support for HTTP NTLM authorization
  --disable-debug         disable support for debugging output
  --disable-nls           do not use Native Language Support
  --disable-largefile     omit support for large files
  --disable-ipv6          disable IPv6 support
  --disable-rpath         do not hardcode runtime library paths

You can inspect decisions made by configure by editing the generated
Makefiles and the `src/config.h' include file.  The defaults should
work without intervention, but if you know what you are doing, editing
the generated files before compilation is fine -- they will not be
regenerated until you run configure again.

`configure' will try to find a compiler in your PATH, defaulting to
`gcc', but falling back to `cc' if the former is unavailable.  This is
a reasonable default on most Unix-like systems, but sometimes you
might want to override it.  The compiler choice is overridden by
setting the `CC' environment variable to the desired compiler file
name.  For example, to force compilation with the Unix `cc' compiler,
invoke configure like this:

    ./configure CC=cc

This assumes that `cc' is in your path -- if it is not, simply use
CC=/path/to/cc instead.  Note that environment variables that affect
configure can be set with the usual shell syntax `VAR=value
./configure' (assuming sh syntax), but can also be specified as
arguments to configure, as shown above.  The latter method, while
being specific to configure, works unmodified in all shells.

Environment variables that affect `configure' include: CFLAGS for C
compiler flags, CPPFLAGS for C preprocessor flags, LDFLAGS for linker
flags, and LIBS for libraries.

Barring the use of --without-* flags, configure will try to autodetect
external libraries needed by Wget, currently only the OpenSSL
libraries.  If they are installed in the system library directories or
in the same prefix where you plan to install Wget, configure should be
able to autodetect them.  If they are installed elsewhere, use the
`--with-libNAME' option to specify the root directory under which
libraries reside in the `lib/' subdirectory and the corresponding
header files reside in the `include/' subdirectory.  For example, if
the OpenSSL libraries are installed under the /usr/local/ssl prefix,
use `--with-libssl=/usr/local/ssl'.

Sometimes external libraries will be installed on the system, but the
header files will be missing.  This often happens on GNU/Linux if you
forget to install the "-devel" or "-dev" package that corresponds to
the library and that is typically *not* installed by default.  In that
case configure will not find the library and you will not be able to
use the features provided by the library until you install the devel
package and rerun configure.  If you believe you have the necessary
headers, but configure still fails to detect the library, please
report it as a bug.

3. Compilation
--------------

To compile GNU Wget after it has been configured, simply type make.
If your compiler is too old to handle function prototypes, Wget will
try to K&R-ize its sources on the fly.  This should make GNU Wget
compilable on almost any Unix-like system you are likely to encounter.

After the compilation a ready-to-use `wget' executable should reside
in the src directory.  At this point there is no formal test suite for
testing the binary, but it should be easy enough to test whether the
basic functionality works.

4. Installation
---------------

Use `make install' to install GNU Wget to directories specified to
configure.  To install it in a system directory (which is the
default), you will need to be root.  The standard prefix is
"/usr/local/", which can be changed using the `--prefix' configure
option.

The installation process will copy the wget binary to $PREFIX/bin,
install the wget.info* info pages to $PREFIX/info, the generated
manual page (where available) wget.1 to $PREFIX/man/man1, and the
default config file to $PREFIX/etc, unless a config file already
exists there.  You can customize these directories either through the
configuration process or making the necessary changes in the Makefile.

To delete the files created by Wget installation, you can use `make
uninstall'.