1lib::core::only(3)    User Contributed Perl Documentation   lib::core::only(3)
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NAME

6       lib::core::only - Remove all non-core paths from @INC to avoid
7       site/vendor dirs
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SYNOPSIS

10         use lib::core::only; # now @INC contains only the two core directories
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12       To get only the core directories plus the ones for the local::lib in
13       scope:
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15         $ perl -mlocal::lib -Mlib::core::only -Mlocal::lib=~/perl5 myscript.pl
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17       To attempt to do a self-contained build (but note this will not
18       reliably propagate into subprocesses, see the CAVEATS below):
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20         $ PERL5OPT='-mlocal::lib -Mlib::core::only -Mlocal::lib=~/perl5' cpan
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22       Please note that it is necessary to use "local::lib" twice for this to
23       work.  First so that "lib::core::only" doesn't prevent "local::lib"
24       from loading (it's not currently in core) and then again after
25       "lib::core::only" so that the local paths are not removed.
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DESCRIPTION

28       lib::core::only is simply a shortcut to say "please reduce my @INC to
29       only the core lib and archlib (architecture-specific lib) directories
30       of this perl".
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32       You might want to do this to ensure a local::lib contains only the code
33       you need, or to test an App::FatPacker tree, or to avoid known bad
34       vendor packages.
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36       You might want to use this to try and install a self-contained tree of
37       perl modules. Be warned that that probably won't work (see "CAVEATS").
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39       This module was extracted from local::lib's --self-contained feature,
40       and contains the only part that ever worked. I apologise to anybody who
41       thought anything else did.
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CAVEATS

44       This does not propagate properly across perl invocations like
45       local::lib's stuff does. It can't. It's only a module import, so it
46       only affects the specific perl VM instance in which you load and
47       import() it.
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49       If you want to cascade it across invocations, you can set the PERL5OPT
50       environment variable to '-Mlib::core::only' and it'll sort of work. But
51       be aware that taint mode ignores this, so some modules' build and test
52       code probably will as well.
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54       You also need to be aware that perl's command line options are not
55       processed in order - -I options take effect before -M options, so
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57         perl -Mlib::core::only -Ilib
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59       is unlike to do what you want - it's exactly equivalent to:
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61         perl -Mlib::core::only
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63       If you want to combine a core-only @INC with additional paths, you need
64       to add the additional paths using -M options and the lib module:
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66         perl -Mlib::core::only -Mlib=lib
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68         # or if you're trying to test compiled code:
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70         perl -Mlib::core::only -Mblib
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72       For more information on the impossibility of sanely propagating this
73       across module builds without help from the build program, see
74       <http://www.shadowcat.co.uk/blog/matt-s-trout/tainted-love> - and for
75       ways to achieve the old --self-contained feature's results, look at
76       App::FatPacker's tree function, and at App::cpanminus's
77       --local-lib-contained feature.
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AUTHOR

80       Matt S. Trout <mst@shadowcat.co.uk>
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LICENSE

83       This library is free software under the same terms as perl itself.
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86       (c) 2010 the lib::core::only "AUTHOR" as specified above.
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90perl v5.34.0                      2021-10-17                lib::core::only(3)
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