use strict;
use warnings;

my @txtfiles = glob "*.txt";
my @criticalfiles;
for my $file (@txtfiles) {
		my $fh;
		if( not open $fh, "<", $file ) {
				print "Cannot open file $file, skipping.\n";
				next;
		}
		while( <$fh> ) {
				if( /critical/ ) {
						push @criticalfiles, $file;
						last;
				}
		}
		close $fh;
}
print "Critical files:\n";
print join( "\n", @criticalfiles ), "\n";