NAME

Sys::Path - supply autoconf style installation directories

SYNOPSIS

Paths for basic Unix installation when Perl is in /usr/bin:

    use Sys::Path;

    print Sys::Path->sysconfdir, "\n";
    # /etc
    print Sys::Path->datadir, "\n";
    # /usr/share
    print Sys::Path->logdir, "\n";
    # /var/log
    print Sys::Path->sharedstatedir, "\n";
    # /var/lib

Paths for Unix when Perl is in home folder /home/daxim/local/bin:

    print Sys::Path->sysconfdir, "\n";
    # /home/daxim/local/etc
    print Sys::Path->datadir, "\n";
    # /home/daxim/local/share
    print Sys::Path->logdir, "\n";
    # /home/daxim/local/log
    print Sys::Path->sharedstatedir, "\n";
    # /home/daxim/local/lib

Paths for MS Windows Strawberry Perl when installed to C:\Strawberry\

    print Sys::Path->sysconfdir, "\n";
    # C:\Strawberry\etc
    print Sys::Path->datadir, "\n";
    # C:\Strawberry\share
    print Sys::Path->logdir, "\n";
    # C:\Strawberry\log
    print Sys::Path->sharedstatedir, "\n";
    # C:\Strawberry\lib

DESCRIPTION

The goal is that Sys::Path provides autoconf style system paths.

The default paths for file locations are based on http://www.pathname.com/fhs/ (Filesystem Hierarchy Standard) if the Perl was installed in /usr. For all other non-standard Perl installations or systems the default prefix is the prefix of Perl it self. Still those are just defaults and can be changed during perl Build.PL prompting. After Sys::Path is configured and installed all programs using it can just read/use the paths.

In addition Sys::Path includes some functions that are related to modules build or installation. For now there is only Module::Build based Module::Build::SysPath that uses Sys::Path.

BUILD TIME CONFIGURATION

    PERL_MM_USE_DEFAULT=1 perl Build.PL \
        --sp-prefix=/usr/local \
        --sp-sysconfdir=/usr/local/etc \
        --sp-localstatedir=/var/local

NOTE

This is an experiment and lot of questions and concerns can come out about the paths configuration. Distributions build systems integration and the naming. And as this is early version things may change. For these purposes there is a mailing list http://lists.meon.sk/mailman/listinfo/sys-path.

WHY?

The filesystem standard has been designed to be used by Unix distribution developers, package developers, and system implementors. However, it is primarily intended to be a reference and is not a tutorial on how to manage a Unix filesystem or directory hierarchy.

Sys::Path follows this standard when it is possible. Or when Perl follows. Perl can be installed in many places. Most Linux distributions place Perl in /usr/bin/perl where FHS suggest. In this case the FHS folders are suggested in prompt when doing `perl Build.PL`. In other cases for other folders or home-folder Perl distributions Sys::Path will suggest folders under Perl install prefix. (ex. c:\strawerry\ for the ones using Windows).

PATHS

Here is the list of paths. First the default FHS path, then (to compare) a suggested path when Perl is not installed in /usr.

prefix

/usr - $Config::Config{'prefix'}

Is a helper function and should not be used directly.

localstatedir

/var - $Config::Config{'prefix'}

Is a helper function and should not be used directly.

sysconfdir

/etc - $prefix/etc

The /etc hierarchy contains configuration files. See http://www.pathname.com/fhs/pub/fhs-2.3.html#ETCHOSTSPECIFICSYSTEMCONFIGURATION.

datadir

/usr/share - $prefix/share

The /usr/share hierarchy is for all read-only architecture independent data files. See http://www.pathname.com/fhs/pub/fhs-2.3.html#USRSHAREARCHITECTUREINDEPENDENTDATA.

docdir

/usr/share/doc - $prefix/share/doc

See "datadir"

localedir

/usr/share/locale - $prefix/share/locale

See "datadir"

cachedir

/var/cache - $localstatedir/cache

/var/cache is intended for cached data from applications. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARCACHEAPPLICATIONCACHEDATA.

logdir

/var/log - $localstatedir/logdir

This directory contains miscellaneous log files. Most logs must be written to this directory or an appropriate subdirectory. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLOGLOGFILESANDDIRECTORIES.

spooldir

/var/spool - $localstatedir/spool

Contains data which is awaiting some kind of later processing. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARSPOOLAPPLICATIONSPOOLDATA.

rundir

/var/run - $localstatedir/rundir

This directory contains system information data describing the system since it was booted. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARRUNRUNTIMEVARIABLEDATA.

lockdir

/var/lock - $localstatedir/lock

Lock files folder. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLOCKLOCKFILES.

sharedstatedir

/var/lib - $localstatedir/lib

The directory for installing modifiable architecture-independent data. See http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLIBVARIABLESTATEINFORMATION.

srvdir

/srv - $prefix/srv

Data for services provided by system. See http://www.pathname.com/fhs/pub/fhs-2.3.html#SRVDATAFORSERVICESPROVIDEDBYSYSTEM.

webdir

/var/www - $localstatedir/www

Directory where distribution put static web files.

HOW IT WORKS

The heart of Sys::Path is just:

    use Config;
    if ($Config::Config{'prefix'} eq '/usr') { ... do stuff ... }

The idea is that if the Perl was installed to /usr it is FHS type installation and all path defaults are made based on FHS. For the rest of the installations prefix and localstatedir is set exactly to $Config::Config{'prefix'} which is the prefix of Perl that was used to install. In this case sysconfdir is set to prefix+'etc'. See Sys::Path::SPc for the implementation.

METHODS

    prefix
    localstatedir
    sysconfdir
    datadir
    docdir
    localedir
    cachedir
    logdir
    spooldir
    rundir
    lockdir
    sharedstatedir
    webdir
    srvdir

BUILDERS/INSTALLERS helper methods

find_distribution_root(__PACKAGE__)

Find the root folder of a modules distribution by going up the folder structure.

prompt_cfg_file_changed($src_file, $dst_file, $prompt_function)

Will prompt if to overwrite $dst_file with $src_file. Returns true for "yes" and false for "no".

changed_since_install($dest_file, $file)

Return if $dest_file changed since install. If optional $file is set then this one is compared against install $dest_file checksum.

install_checksums(%filenames_with_checksums)

Getter and setter for files checksums recording.

SEE ALSO

Module::Build::SysPath

AUTHOR

Jozef Kutej, <jkutej at cpan.org>

CONTRIBUTORS

The following people have contributed to the Sys::Path by committing their code, sending patches, reporting bugs, asking questions, suggesting useful advises, nitpicking, chatting on IRC or commenting on my blog (in no particular order):

    Lars Dɪᴇᴄᴋᴏᴡ 迪拉斯
    Emmanuel Rodriguez
    Salve J. Nilsen
    Daniel Perrett

COPYRIGHT & LICENSE

Copyright 2009 Jozef Kutej, all rights reserved.

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

cpanm Sys::Path

perl -MCPAN -e shell
install Sys::Path