NAME
    Shell::Config::Generate - Portably generate config for any shell

VERSION
    version 0.08

SYNOPSIS
    With this start up:

     use Shell::Guess;
     use Shell::Config::Generate;
 
     my $config = Shell::Config::Generate->new;
     $config->comment( 'this is my config file' );
     $config->set( FOO => 'bar' );
     $config->set_path(
       PERL5LIB => '/foo/bar/lib/perl5',
                   '/foo/bar/lib/perl5/perl5/site',
     );
     $config->append_path(
       PATH => '/foo/bar/bin',
               '/bar/foo/bin',
     );

    This:

     $config->generate_file(Shell::Guess->bourne_shell, 'config.sh');

    will generate a config.sh file with this:

     # this is my config file
     FOO='bar';
     export FOO;
     PERL5LIB='/foo/bar/lib/perl5:/foo/bar/lib/perl5/perl5/site';
     export PERL5LIB;
     if [ -n "$PATH" ] ; then
       PATH=$PATH:'/foo/bar/bin:/bar/foo/bin';
       export PATH
     else
       PATH='/foo/bar/bin:/bar/foo/bin';
       export PATH;
     fi;

    and this:

     $config->generate_file(Shell::Guess->c_shell, 'config.csh');

    will generate a config.csh with this:

     # this is my config file
     setenv FOO 'bar';
     setenv PERL5LIB '/foo/bar/lib/perl5:/foo/bar/lib/perl5/perl5/site';
     test "$?PATH" = 0 && setenv PATH '/foo/bar/bin:/bar/foo/bin' || setenv PATH "$PATH":'/foo/bar/bin:/bar/foo/bin';

    and this:

     $config->generate_file(Shell::Guess->cmd_shell, 'config.cmd');

    will generate a "config.cmd" (Windows "cmd.exe" script) with this:

     rem this is my config file
     set FOO=bar
     set PERL5LIB=/foo/bar/lib/perl5;/foo/bar/lib/perl5/perl5/site
     if defined PATH (set PATH=%PATH%;/foo/bar/bin;/bar/foo/bin) else (set PATH=/foo/bar/bin;/bar/foo/bin)

DESCRIPTION
    This module provides an interface for specifying shell configurations
    for different shell environments without having to worry about the
    arcane differences between shells such as csh, sh, cmd.exe and
    command.com.

    It does not modify the current environment, but it can be used to create
    shell configurations which do modify the environment.

    This module uses Shell::Guess to represent the different types of shells
    that are supported. In this way you can statically specify just one or
    more shells:

     #!/usr/bin/perl
     use Shell::Guess;
     use Shell::Config::Generate;
     my $config = Shell::Config::Generate->new;
     # ... config config ...
     $config->generate_file(Shell::Guess->bourne_shell,  'foo.sh' );
     $config->generate_file(Shell::Guess->c_shell,       'foo.csh');
     $config->generate_file(Shell::Guess->cmd_shell,     'foo.cmd');
     $config->generate_file(Shell::Guess->command_shell, 'foo.bat');

    This will create foo.sh and foo.csh versions of the configurations,
    which can be sourced like so:

     #!/bin/sh
     . ./foo.sh

    or

     #!/bin/csh
     source foo.csh

    It also creates ".cmd" and ".bat" files with the same configuration
    which can be used in Windows. The configuration can be imported back
    into your shell by simply executing these files:

     C:\> foo.cmd

    or

     C:\> foo.bat

    Alternatively you can use the shell that called your Perl script using
    Shell::Guess's "running_shell" method, and write the output to standard
    out.

     #!/usr/bin/perl
     use Shell::Guess;
     use Shell::Config::Generate;
     my $config = Shell::Config::Generate->new;
     # ... config config ...
     print $config->generate(Shell::Guess->running_shell);

    If you use this pattern, you can eval the output of your script using
    your shell's back ticks to import the configuration into the shell.

     #!/bin/sh
     eval `script.pl`

    or

     #!/bin/csh
     eval `script.pl`

CONSTRUCTOR
  Shell::Config::Generate->new
    creates an instance of She::Config::Generate.

METHODS
    There are two types of instance methods for this class:

    *   modifiers

        adjust the configuration in an internal portable format

    *   generators

        generate shell configuration in a specific format given the internal
        portable format stored inside the instance.

    The idea is that you can create multiple modifications to the
    environment without worrying about specific shells, then when you are
    done you can create shell specific versions of those modifications using
    the generators.

    This may be useful for system administrators that must support users
    that use different shells, with a single configuration generation script
    written in Perl.

  $config->set( $name => $value )
    Set an environment variable.

  $config->set_path( $name => @values )
    Sets an environment variable which is stored in standard 'path' format
    (Like PATH or PERL5LIB). In UNIX land this is a colon separated list
    stored as a string. In Windows this is a semicolon separated list stored
    as a string. You can do the same thing using the "set" method, but if
    you do so you have to determine the correct separator.

    This will replace the existing path value if it already exists.

  $config->append_path( $name => @values );
    Appends to an environment variable which is stored in standard 'path'
    format. This will create a new environment variable if it doesn't
    already exist, or add to an existing value.

  $config->prepend_path( $name => @values );
    Prepend to an environment variable which is stored in standard 'path'
    format. This will create a new environment variable if it doesn't
    already exist, or add to an existing value.

  $config->comment( $comment )
    This will generate a comment in the appropriate format.

    note that including comments in your configuration may mean it will not
    work with the "eval" backticks method for importing configurations into
    your shell.

  $config->shebang( [ $location ] )
    This will generate a shebang at the beginning of the configuration,
    making it appropriate for use as a script. For non UNIX shells this will
    be ignored. If specified, $location will be used as the interpreter
    location. If it is not specified, then the default location for the
    shell will be used.

    note that the shebang in your configuration may mean it will not work
    with the "eval" backticks method for importing configurations into your
    shell.

  $config->echo_off
    For DOS/Windows configurations ("command.com" or "cmd.exe"), issue this
    as the first line of the config:

     @echo off

  $config->echo_on
    Turn off the echo off (that is do not put anything at the beginning of
    the config) for DOS/Windows configurations ("command.com" or "cmd.exe").

  $config->generate( [ $shell ] )
    Generate shell configuration code for the given shell. $shell is an
    instance of Shell::Guess. If $shell is not provided, then this method
    will use Shell::Guess to guess the shell that called your perl script.

  $config->generate_file( $shell, $filename )
    Generate shell configuration code for the given shell and write it to
    the given file. $shell is an instance of Shell::Guess. If there is an IO
    error it will throw an exception.

CAVEATS
    The test suite tests this module's output against the actual shells that
    should understand them, if they can be found in the path. You can
    generate configurations for shells which are not available (for example
    "cmd.exe" configurations from UNIX or bourne configurations under
    windows), but the test suite only tests them if they are found during
    the build of this module.

    The implementation for "csh" depends on the external command "test". As
    far as I can tell "test" should be available on all modern flavors of
    UNIX which are using "csh". If anyone can figure out how to prepend or
    append to path type environment variable without an external command in
    "csh", then a patch would be appreciated.

    The incantation for prepending and appending elements to a path on csh
    probably deserve a comment here. It looks like this:

     test "$?PATH" = 0 && setenv PATH '/foo/bar/bin:/bar/foo/bin' || setenv PATH "$PATH":'/foo/bar/bin:/bar/foo/bin';

    *   one line

        The command is all on one line, and doesn't use if, which is
        probably more clear and ideomatic. This for example, might make more
        sense:

         if ( $?PATH == 0 ) then
           setenv PATH '/foo/bar/bin:/bar/foo/bin' 
         else
           setenv PATH "$PATH":'/foo/bar/bin:/bar/foo/bin'
         endif

        However, this only works if the code interpreted using the csh
        "source" command or is included in a csh script inline. If you try
        to invoke this code using csh "eval" then it will helpfully convert
        it to one line and if does not work under csh in one line.

    There are probably more clever or prettier ways to append/prepend path
    environment variables as I am not a shell programmer. Patches welcome.

    Only UNIX and Windows are supported so far. Patches welcome.

AUTHOR
    Graham Ollis <plicease@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2012 by Graham Ollis.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

