how to make cpan modules available in cron

My perl script, jaw20230325printcalendartodisk.pl,
depends on File::Rsync.
I had to do cpan File::Rsync to get this module on my computer,
which is macbook pro, macos Ventura 13.4.

The script
jaw20230325printcalendartodisk.pl
does not directly use File::Rsync but
rather uses a perl module I wrote,
QuemQuaeritis.pm,
which uses File::Rsync.

jaw20230325printcalendartodisk.pl
runs fine on the command line.
But I want to run it under cron:

> crontab -l
00 16  *  *  *  $HOME/u/kh/pm/jaw20230325printcalendartodisk.pl

and this leads to the following error:

Can't locate File/Rsync.pm in @INC (you may need to install the File::Rsync module) (@INC contains: /Users/kpr/u/kh/pm
/usr/local/opt/perl/lib/perl5/site_perl/5.36/darwin-thread-multi-2level /usr/local/opt/perl/lib/perl5/site_perl/5.36
/usr/local/opt/perl/lib/perl5/5.36/darwin-thread-multi-2level /usr/local/opt/perl/lib/perl5/5.36 /usr/local/lib/perl5/site_perl/5.36) at
/Users/kpr/u/kh/pm/QuemQuaeritis.pm line 2061.
BEGIN failed--compilation aborted at /Users/kpr/u/kh/pm/QuemQuaeritis.pm line 2061.
Compilation failed in require at /Users/kpr/u/kh/pm/jaw20230325printcalendartodisk.pl line 39.
BEGIN failed--compilation aborted at /Users/kpr/u/kh/pm/jaw20230325printcalendartodisk.pl line 39.

So it appears that cpan made File::Rsync available in my shell, but not under cron.

jaw20230325printcalendartodisk.pl used to run fine under cron, but
this week
I did brew install python on this machine.
It then installed something called python3.
Only
after that installation did my code stop running under cron.

Based on warnings that were printed when I ran cpan,
the following has been the final line in my .bash_profile for four months:

eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib=$HOME/perl5)"

This is supposed to mean that I do not have to reinstall modules each time the macos is upgraded.

Thus, how do I make my cpan modules available under cron, i.e., when I am not running in the shell?

Or alternatively, how can I prevent an installation of
python3 from interfering with the accessibility of my
cpan-installed perl modules?

Additional information:

> perldoc -l File::Rsync
/Users/kpr/perl5/lib/perl5/File/Rsync.pm

I believe this is consistent with the final line of .bash_profile above.
I think that line means that when I install a module under cpan,
it is put under my HOME directory, not where the rest of perl is installed.

Add the following to your crontab:

PERL5LIB=/Users/kpr/perl5/lib/perl5

Or possibly

PERL5LIB=$HOME/perl5/lib/perl5

This will have the same effect local::lib. (Well, the relevant part of it. You can run perl -I$HOME/perl5/lib/perl5 -Mlocal::lib=$HOME/perl5 to see all the vars it sets.)

Jobs run out of crontab(5) are in a restricted environment and a program cannot simply rely on the user's shell environment and configuration. One way out of that is to set up everything in the program.

When the interpreter needs to load a module it searches paths given in the global @INC array for it. In this case it'll look for a directory File and then for a file Rsync.pm in it. Also see require, and perlmod.

So if this module is installed in a location which isn't already in @INC then one needs to add to @INC that path, in which File/Rsync.pm is. The best way to do that is via the lib pragma.

The question gives the module's location as /Users/kpr/perl5/lib/perl5/File/Rsync.pm so

use lib '/Users/kpr/perl5/lib/perl5';

use File::Rsync;

Now this should be able to run via cron.

A comment clarifies that /Users/kpr is the home directory, as it may seem. Then it is indeed better to use $ENV{HOME} instead,

use lib "$ENV{HOME}/perl5/lib/perl5";

More specifically, the comment states that this is different on other machines (so on those machines the module is installed in different directories), and then this also makes it a good example of portability issues.

@ikegami's answer will almost certainly work for you, but another (more general) solution is to get cron to run a command via your shell. This ensures that all the usual environment your shell provides for you will be available.

Something like this in crontab:

00 16 *  *  *  /usr/bin/bash -c "$HOME/u/kh/pm/jaw20230325printcalendartodisk.pl"

This is slightly less efficient, but for a script run once per day, a few extra microseconds of runtime is likely not a concern.

Recall that
QuemQuaeritis.pm holds the subs for my module,
including the sub that was trying to run when I got the error.

The script that ran under my shell but not in crontab invoked a sub that contained
use File::Rsync;.
It was at that line that the error was thrown under cron/crontab.

Thanks to comments, I put the following into the early lines of QuemQuaeritis.pm :

use lib $ENV{HOME} . '/perl5/lib/perl5/';

and then my script ran fine under cron.