+# generate a regex from a shell type expression
+# see 'perl cookbook' 6.9
+sub shellregex
+{
+ my $in = shift;
+ $in =~ s{(.)} { $patmap{$1} || "\Q$1" }ge;
+ return '^' . $in . "\$";
+}
+
+# start an attempt at determining whether this string might be a callsign
+sub iscallsign
+{
+ my $call = shift;
+ return 1 if $call =~ /^\w+\d+/;
+ return 1 if $call =~ /^\d+\w+/;
+ return undef;
+}
+
+# read in a file into a string and return it.
+# the filename can be split into a dir and file and the
+# file can be in upper or lower case.
+# there can also be a suffix
+sub readfilestr
+{
+ my ($dir, $file, $suffix) = @_;
+ my $fn;
+
+ if ($suffix) {
+ $fn = "$dir/$file.$suffix";
+ unless (-e $fn) {
+ my $f = uc $file;
+ $fn = "$dir/$file.$suffix";
+ }
+ } elsif ($file) {
+ $fn = "$dir/$file";
+ unless (-e $fn) {
+ my $f = uc $file;
+ $fn = "$dir/$file";
+ }
+ } else {
+ $fn = $dir;
+ }
+ my $fh = new IO::File $fn;
+ my $s = undef;
+ if ($fh) {
+ local $/ = undef;
+ $s = <$fh>;
+ $fh->close;
+ }
+ return $s;
+}