Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

File::Which(3)                       User Contributed Perl Documentation                      File::Which(3)



NAME
       File::Which - Portable implementation of the `which' utility

SYNOPSIS
         use File::Which;                  # exports which()
         use File::Which qw(which where);  # exports which() and where()

         my $exe_path = which('perldoc');

         my @paths = where('perl');
         - Or -my Ormy
         my @paths = which('perl'); # an array forces search for all of them

DESCRIPTION
       "File::Which" was created to be able to get the paths to executable programs on systems under which
       the `which' program wasn't implemented in the shell.

       "File::Which" searches the directories of the user's "PATH" (as returned by "File::Spec->path()"),
       looking for executable files having the name specified as a parameter to "which()". Under Win32
       systems, which do not have a notion of directly executable files, but uses special extensions such as
       ".exe" and ".bat" to identify them, "File::Which" takes extra steps to assure that you will find the
       correct file (so for example, you might be searching for "perl", it'll try perl.exe, perl.bat, etc.)

Steps Used on Win32, DOS, OS2 and VMS
   Windows NT
       Windows NT has a special environment variable called "PATHEXT", which is used by the shell to look
       for executable files. Usually, it will contain a list in the form ".EXE;.BAT;.COM;.JS;.VBS" etc. If
       "File::Which" finds such an environment variable, it parses the list and uses it as the different
       extensions.

   Windows 9x and other ancient Win/DOS/OS2
       This set of operating systems don't have the "PATHEXT" variable, and usually you will find executable
       files there with the extensions ".exe", ".bat" and (less likely) ".com". "File::Which" uses this
       hardcoded list if it's running under Win32 but does not find a "PATHEXT" variable.

   VMS
       Same case as Windows 9x: uses ".exe" and ".com" (in that order).

Functions
   which($short_exe_name)
       Exported by default.

       $short_exe_name is the name used in the shell to call the program (for example, "perl").

       If it finds an executable with the name you specified, "which()" will return the absolute path
       leading to this executable (for example, /usr/bin/perl or C:\Perl\Bin\perl.exe).

       If it does not find the executable, it returns "undef".

       If "which()" is called in list context, it will return all the matches.

   where($short_exe_name)
       Not exported by default.

       Same as "which($short_exe_name)" in array context. Same as the `where' utility, will return an array
       containing all the path names matching $short_exe_name.

BUGS AND CAVEATS
       Not tested on VMS or MacOS, although there is platform specific code for those. Anyone who haves a
       second would be very kind to send me a report of how it went.

       File::Spec adds the current directory to the front of PATH if on Win32, VMS or MacOS. I have no
       knowledge of those so don't know if the current directory is searced first or not. Could someone
       please tell me?

SUPPORT
       Bugs should be reported via the CPAN bug tracker at

       http://rt.cpan.org/NoAuth/ReportBug.html?Queue=File-Which
       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=File-Which>

       For other issues, contact the maintainer.

AUTHOR
       Adam Kennedy <adamk@cpan.org>

       Per Einar Ellefsen <pereinar@cpan.org>

       Originated in modperl-2._/lib/Apache/Build.pm. Changed for use in DocSet (for the mod_perl site) and
       Win32-awareness by me, with slight modifications by Stas Bekman, then extracted to create
       "File::Which".

       Version 0.04 had some significant platform-related changes, taken from the Perl Power Tools `which'
       implementation by Abigail with enhancements from Peter Prymmer. See
       <http://www.perl.com/language/ppt/src/which/index.html> for more information.

COPYRIGHT
       Copyright 2002 Per Einar Ellefsen.

       Some parts copyright 2009 Adam Kennedy.

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

SEE ALSO
       File::Spec, which(1), Perl Power Tools: <http://www.perl.com/language/ppt/index.html>.



perl v5.16.2                                     2009-09-26                                   File::Which(3)