pgrep: do_file

• The first half is just argument processing

 sub do_file {
 my $file = shift;
 my $fh;
 if (ref $file) {
 $fh = $file;
 $file = "<stdin>";
 } else {
 return if -d $file;
 unless (open $fh, "<", $file) {
 warn "Couldn't open '$file': $!; skipping\n";
 return;
 }
 }

• The function now has a filehandle to work with

• The pattern matching is all here:

 while (<$fh>) {
 chomp;
 if (/$qr/ ^ $opt_v) {
 $rc = 0; # match
 printf $format, $file, $_, $.;
 return if $opt_l;
 }
 }
 }

• The /$qr/ ^ $opt_v thing harks back to $REVERSE in sortby