As found on chiark in /usr/local/lib/news/feed+read/newsrc-listgroups

diff --git a/newsrc-lg/newsrc-listgroups b/newsrc-lg/newsrc-listgroups
new file mode 100755 (executable)
index 0000000..73ad841
--- /dev/null
+++ b/newsrc-lg/newsrc-listgroups
@@ -0,0 +1,37 @@
+#!/usr/bin/perl
+
+$minreaddays= 21;
+$maxperuser= 250;
+
+open(CONF,"$ARGV[0]") or die $!;
+while(<CONF>) {
+    next if m/^\#/ || !m/^\S/;
+    next if m/^(myfqdn|xref|server|server-nosearch|fetch|read|post|permit|believe|extrarc)\s/;
+    if (m/^minreaddays\s+(\d+)\s+$/) {
+        $minreaddays= $1;
+    } elsif (m/^maxperuser\s+(\d+)\s+$/) {
+        $maxperuser= $1;
+    } else {
+        die "$_ ?";
+    }
+}
+
+$newsrc= ".newsrc";
+exit 0 if -l $newsrc || ! -f _ || -M _ > $minreaddays;
+
+@g= ();
+
+open NEWSRC, $newsrc or die $!;
+while (<NEWSRC>) {
+    next unless s/:.*\n$//;
+    next unless m/^[-a-z0-9+]+\.[-a-z0-9+._]+$/i;
+    push @g, "$_\n";
+}
+close NEWSRC or die $!;
+
+exit 0 if @g > $maxperuser;
+
+print sort @g or die $!;
+close STDOUT or die $!;
+
+exit 0;