Hoi, thanks for pointing to that! I would have missed it but now I had a good laugh. :-) Just for the record, it's that one: https://xkcd.com/1638/ Grepped* my troff sources and found no more than four backslashes in a row, but at least I got 16 in one line: .ds _O '\f(SCChapter \\\\n(H1\ \ \\\\*(_C\fP''\\\\n(PN' \" right Seems I haven't gone deep enough into troff to need more than four backslashes to manage my way back up into daylight. :-) The Heirloom doctools' mm macros impress a lot more. They have 16 subsequent (!) backslashes: $ fgrep '\\\\\\\\\\\\\\\\' /usr/local/lib/doctools/tmac/* /usr/local/lib/doctools/tmac/mmn:\!\\!.if \\$2=\\\\\\\\\\\\\\\\$1 .)T 1 1 "\\*(}0" "\\$4" \\\\\\\\nP \\*(}3 /usr/local/lib/doctools/tmac/mmt:\!\\!.if \\$2=\\\\\\\\\\\\\\\\$1 .)T 1 1 "\\*(}0" "\\$4" \\\\\\\\nP \\*(}3 You see, this XKCD cartoon is definitely about troff! meillo *) Nice thread about grep, btw.