man page — Scan file prerequisites


    % *.pm          # Print PREREQ_PM section for *.pm
    % -e 'STRING'   # Scan an one-liner
    % -B *.pm       # Include core modules
    % -V *.pm       # Show autoload/shared/data files
    % -R *.pm       # Don't recurse
    % -C CACHEFILE  # use CACHEFILE to cache dependencies

Description is a simple-minded utility that prints out the "PREREQ_PM" section needed by modules.

If the option "-T" is specified and you have CPANPLUS installed, modules that are part of an earlier module's distribution with be denoted with "S"; modules without a distribution name on CPAN are marked with "?".

Also, if the "-B" option is specified, module belongs to a perl distribution on CPAN (and thus uninstallable by "" or "") are marked with "C".

Finally, modules that has loadable shared object files (usually needing a compiler to install) are marked with "X"; with the "-V" flag, those files (and all other files found) will be listed before the main output. Additionally, all module files that the scanned code depends on but were not found (and thus not scanned recursively) are listed. These may include genuinely missing modules or false positives. That means, modules your code does not depend on (on this particular platform) but that were picked up by the heuristic anyway.


-e, --eval=STRING

Scan STRING as a string containing perl code.

-c, --compile

Compiles the code and inspects its %INC, in addition to static scanning.

-x, --execute

Executes the code and inspects its %INC, in addition to static scanning. You may use --xargs to specify @ARGV when executing the code.


If -x is given, splits the "STRING" using the function  "shellwords" from Text::ParseWords and passes the result  as @ARGV when executing the code.

-B, --bundle

Include core modules in the output and the recursive search list.

-R, --no-recurse

Only show dependencies found in the files listed and do not recurse.

-V, --verbose

Verbose mode: Output all files found during the process;  show dependencies between modules and availability.

Additionally, warns of any missing dependencies. If you find missing dependencies that aren't really dependencies, you have probably found false positives.

-C, --cachedeps=CACHEFILE

Use CACHEFILE to speed up the scanning process by caching dependencies. Creates CACHEFILE if it does not exist yet.

-T, --modtree

Retrieves module information from CPAN if you have CPANPLUS installed.

See Also

Module::ScanDeps, CPANPLUS::Backend, PAR


Simon Cozens, for suggesting this script to be written.


Audrey Tang <>


2016-09-19 perl v5.24.1 User Contributed Perl Documentation