Here's a version that only keeps one line in memory at a time (as opposed to every match). It is done elegantly (from the perspective of the function's user) using an iterator.
use strict;
use warnings;
use File::Glob qw( bsd_glob );
sub search_files {
my ($re, @files) = @_;
my $fh;
my $file_name;
return sub {
START:
if (not defined $file_name) {
return () if not @files;
$file_name = shift(@files);
if (!open($fh, '<', $file_name)) {
warn("Unable to open file \"$file_name\": $!\n");
undef $file_name;
goto START;
}
}
while (defined(my $line = <$fh>)) {
if ($line =~ /$re/) {
return ( $file_name, $., $line );
}
}
undef $fh;
undef $file_name;
goto START;
};
}
{
my @files = bsd_glob('*');
my $re = qr/^source*/;
my $iter = search_files($re, @files);
while (my ($file_name, $line_num, $line) = $iter->()) {
print("$file_name,$line_num: $line");
}
}