Question

My script runs this command which always gives three warnings. Is there a way to filter these out?

my $output = `cleartool mktag -view -tag test -reg win_region -host view_server1 -gpath \\\\view_server\\view_directory1\\test.vws/viewstore/view_directory1/test.vws\` 

The warnings look something like this:

cleartool: warning: The global pathname "blabla" in the non-default region will not be validated
cleartool: warning: Unable to access "blabla": No such file or directory
cleartool: warning: Storage pathname "blabla" may not reside on host

Answer 1

Assuming the external tool writes to STDERR you can tell the shell to redirect that somewhere else. The usual way to do that is to append 2> /dev/null to the command you’re running via the backticks.

If you need other warnings and errors then capture STDERR in a temporary file (see File::Temp for how to safely generate temporary files) by redirecting 2> $temp_file_name, read that file with Perl (see File::Slurp or IO::All for easy-to-use one liners for reading files like my @captured_stderr = read_file($temporary_file_name);), throw away the lines to you not need with Perl’s grep function and output the remaining lines back to STDERR with print STDERR @captured_stderr).