This can be done quite easily using the magnificent tool: Perl::MinimumVersion by Neil Bowers.
The distribution includes the CLI tool perlver.
You can use it on a single file:
± perlver lib/Test/Timer.pm
------------------------------------------------
| file | explicit | syntax | external |
| ------------------------------------------------ |
| lib/Test/Timer.pm | ~ | v5.6.0 | n/a |
| ------------------------------------------------ |
| Minimum explicit version : ~ |
| Minimum syntax version : v5.6.0 |
| Minimum version of perl : v5.6.0 |
------------------------------------------------Or you can use it on a directory, your distribution for example. Do note that this is not as fast as it is useful.
$ perlver .
-----------------------------------------------------------------
| file | explicit | syntax | external |
| ----------------------------------------------------------------- |
| t/test-tester.t | ~ | v5.6.0 | n/a |
| t/time_alert.t | ~ | v5.6.0 | n/a |
| t/_benchmark.t | ~ | v5.5.3 | n/a |
| t/Test/Timer/Test.pm | ~ | v5.6.0 | n/a |
| prototypes/benchmark.pl | ~ | v5.6.0 | n/a |
| prototypes/time_ok.pl | ~ | v5.6.0 | n/a |
| prototypes/time_between.pl | ~ | v5.6.0 | n/a |
| prototypes/time_atleast.pl | ~ | v5.6.0 | n/a |
| prototypes/time_atmost.pl | ~ | v5.6.0 | n/a |
| prototypes/list_context.pl | ~ | v5.6.0 | n/a |
| prototypes/time_nok.pl | ~ | v5.6.0 | n/a |
| prototypes/regex.pl | ~ | v5.6.0 | n/a |
| lib/Test/Timer.pm | ~ | v5.6.0 | n/a |
| lib/Test/Timer/TimeoutException.pm | ~ | v5.6.0 | n/a |
| ----------------------------------------------------------------- |
| Minimum explicit version : ~ |
| Minimum syntax version : v5.6.0 |
| Minimum version of perl : v5.6.0 |
-----------------------------------------------------------------And as you can read the minimum is provided to you.
If you want to find out as to why a certain version is required you can use the --explain flag.
$ perlver --blame lib/Test/Timer.pm
------------------------------------------------------------
File : lib/Test/Timer.pm
Line : 3
Char : 1
Rule : _perl_5006_pragmas
Version : 5.006
------------------------------------------------------------
use warnings;
------------------------------------------------------------Remember to specify in your minimum requirements in your distribution requirements or similar afterwards.