...

opendir(FOO, "/bar/baz");

my @files = readdir FOO;

closedir FOO;

foreach my $file (@files){

  chomp $file;

  die $predefined_die_msg if $file =~ /^file_name$/i;

}

...

##</code><code>##

#-------------
perl -e 's=$;$/=$\;W=i;$\=$/;s;;XYW\\U$"\;\);sig,$_^=$[x5,print;'