#!/usr/bin/perl -w
#
# addPath: add a path item to a given variable, delimited by colons, if
#    not already there. Warn if it doesn't exist as a directory.
#
#
# Usage:
#    addPath varname dir
# Typically:
#    PATH=`addPath PATH /my/bin`

use strict;

if ($ARGV[0] =~ m/^-+h/) {
    system "perldoc addToPath";
    exit;
}

my $var = $ARGV[0];
my $dir = $ARGV[1];

if ($ARGV[1] eq "") {
	die "Must specify env variable to extend, and path to add.\n";
}

my $oldvar = $ENV{$var};

if (-d $dir == 0) {
	warn "\n'$dir' is not a directory, not added to \$$var.\n";
	exit;
}

if (":$var:" =~ /:$dir:/) {
	exit; # already there
}

$var = "$oldvar:$dir";
print "$var";

exit;


sub showUsage {
	print "

=head1 Usage

    PATH=`addPath PATH [path-to-add]

Adds the given path to the end of any path variable (shown as PATH, but
CDPATH, CLASSPATH, MANPATH, etc. can be substituted). 
Will not add if it's already there.

=head1 Warning

    You need to do it with `` as shown, because the script can't change the
    actual variable directly for the shell it's called from.
";
}