1lib::core::only(3) User Contributed Perl Documentation lib::core::only(3)
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6 lib::core::only - Remove all non-core paths from @INC to avoid
7 site/vendor dirs
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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
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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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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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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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80 Matt S. Trout <mst@shadowcat.co.uk>
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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 v5.26.3 2015-05-28 lib::core::only(3)