Shell::Config::Generate - Portably generate config for any shell
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', ); $config->append_path( PATH => '/foo/bar/bin', '/bar/foo/bin', );
will generate a config.sh file with this:
# this is my config file FOO='bar'; export FOO; PERL5LIB='/foo/bar/lib/perl5:/foo/bar/lib/perl5/perl5/site'; export PERL5LIB; if [ -n "$PATH" ] ; then PATH=$PATH:'/foo/bar/bin:/bar/foo/bin'; export PATH else PATH='/foo/bar/bin:/bar/foo/bin'; export PATH; fi;
will generate a config.csh with this:
# this is my config file setenv FOO 'bar'; setenv PERL5LIB '/foo/bar/lib/perl5:/foo/bar/lib/perl5/perl5/site'; test "$?PATH" = 0 && setenv PATH '/foo/bar/bin:/bar/foo/bin' || setenv PATH "$PATH":'/foo/bar/bin:/bar/foo/bin';
will generate a
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)
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
#!/bin/csh source foo.csh
It also creates
.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:
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`
#!/bin/csh eval `script.pl`
creates an instance of She::Config::Generate.
There are two types of instance methods for this class:
adjust the configuration in an internal portable format
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.
Set an environment variable.
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.
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.
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.
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.
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.
For DOS/Windows configurations (
cmd.exe), issue this as the first line of the config:
Turn off the echo off (that is do not put anything at the beginning of the config) for DOS/Windows configurations (
Sets the given alias to the given command.
Caveat: some older shells do not support aliases, such as the original bourne shell. This module will generate aliases for those shells anyway, since /bin/sh may actually be a more modern shell that DOES support aliases, so do not use this method unless you can be reasonable sure that the shell you are generating supports aliases. On Windows, for PowerShell, a simple function is used instead of an alias so that arguments may be specified.
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.
Generate shell configuration code for the given shell and write it to the given file. $shell is an instance of Shell::Guess. If there is an IO error it will throw an exception.
The test suite tests this module's output against the actual shells that should understand them, if they can be found in the path. You can generate configurations for shells which are not available (for example
cmd.exe configurations from UNIX or bourne configurations under windows), but the test suite only tests them if they are found during the build of this module.
The implementation for
csh depends on the external command
test. As far as I can tell
test should be available on all modern flavors of UNIX which are using
csh. If anyone can figure out how to prepend or append to path type environment variable without an external command in
csh, then a patch would be appreciated.
The incantation for prepending and appending elements to a path on csh probably deserve a comment here. It looks like this:
test "$?PATH" = 0 && setenv PATH '/foo/bar/bin:/bar/foo/bin' || setenv PATH "$PATH":'/foo/bar/bin:/bar/foo/bin';
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 (bourne, bash, csh, ksh, fish and their derivatives) and Windows (command.com, cmd.exe and PowerShell) are supported so far.
Fish shell support should be considered a tech preview. The Fish shell itself is somewhat in flux, and thus some tests are skipped for the Fish shell since behavior is different for different versions. In particular, new lines in environment variables may not work on newer versions.
Patches welcome for your favorite shell / operating system.
Graham Ollis <firstname.lastname@example.org>
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.