Changing @INC path detail

tytower has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Changing @INC path detail by gamache (Friar) on Dec 05, 2007 at 20:36 UTC
The preferred way to add directories to @INC is like this: `use lib qw(/path/to/dir1 /path/to/dir2 ...);` [download] There's documentation here.	[reply] [d/l]
Re: Changing @INC path detail by dynamo (Chaplain) on Dec 05, 2007 at 20:54 UTC
use lib is the Right way to do it, but you can also do it the same way you manipulate any other array: `my $override_lib_path = "/usr/local/Perl/5.8.6/whatever"; my $backup_lib_path = "/lastresort/path/to/lib"; # look in $override_lib_path first unshift @INC, $override_lib_path; # look in $backup_lib_path last if # no match for a module name is found first push @INC, $backup_lib_path;` [download] Good luck.	[reply] [d/l]
Re^2: Changing @INC path detail by moritz (Cardinal) on Dec 05, 2007 at 21:00 UTC
You have to take care that you fold that into a `BEGIN` block, because use is evaluated at compile time. If you have a script like this: `# modify @INC use Some::Module;` [download] the `use` is evaluated before the `# modify @ING` line. You see, it's not as easy at it looks, which is why `use lib $path;` is recommended. (It checks for duplicate entries in `@INC` as well, which is another advantage).	[reply] [d/l] [select]
Re: Changing @INC path detail by sh1tn (Priest) on Dec 05, 2007 at 20:57 UTC
In addition - the pragma itself - lib.	[reply]
Re: Changing @INC path detail by bart (Canon) on Dec 06, 2007 at 13:07 UTC
Alternatively to lib or direct manipulation of @INC, you can provide the -I command line switch... Just `-I` plus the directory path, as one word or with whitespace between them, and optionally quoted. The PERL5OPT environment variable can automatically include it on every script you run (except under -T — taint checks).	[reply] [d/l]
Re: Changing @INC path detail by graq (Curate) on Dec 06, 2007 at 08:52 UTC
If you have some code that you want to flip between using different library paths, you can make it `$ENV` dependent. `BEGIN { $ENV{$_} && unshift @INC, $ENV{$_} for (qw\|DEVA_OR_DEVB\|); }` [download] Setting up `$ENV` will depend on your OS / server environment. -=( Graq )=-	[reply] [d/l] [select]