http://www.perlmonks.org?node_id=91825


in reply to Catching STDERR

The aforementioned methods will work great if you want to redirect STDERR to a file. However, if you want to redirect it to a file AND still display it on the STDERR device (e.g. the screen) you might try Filter::Handle. It will let you attach a sub to a file handle (including STDERR) so that you can print the output to a file or filter it any way you like in addition to printing to the terminal. Here's a little snippet to get you started.
use warnings; use strict; use Filter::Handle qw/subs/; open (LOGFILE, ">logfile") || die "could not open logfile"; #filter STDERR through an anonymous sub Filter \*STDERR, sub {local $_ = "@_"; print LOGFILE "Filtered: $_ "; +$_}; #prints to both STDERR and to LOGFILE print STDERR "error!\n"; #STDERR will no longer be filtered through your sub UnFilter \*STDERR; close LOGFILE;
Regards,
Rhet