$ perl -Mstrict -Mwarnings -E 'my $fileName; my $re = qr{3B4[0|1|2]RT\.\d{10}\.\d+R?\.bin}; $fileName = "3B40RT.2000033121.7.bin.gz"; say +($fileName =~ /$re/) ? "match" : "no match"; $fileName = "3B40RT.2000033121.7R.bin.gz"; say +($fileName =~ /$re/) ? "match" : "no match"; ' match match #### $ perl -Mstrict -Mwarnings -E 'my $fileName; my $re = qr{3B4[0-2]RT\.\d{10}\.\d+R?\.bin}; $fileName = "3B40RT.2000033121.7.bin.gz"; say +($fileName =~ /$re/) ? "match" : "no match"; $fileName = "3B40RT.2000033121.7R.bin.gz"; say +($fileName =~ /$re/) ? "match" : "no match"; ' match match