To be fair, /usr/bin/awk was mawk for a long time with Ubuntu. I remember getting in a heated discussion with GAWK’s maintainer that he should allow a way for [

To be fair, /usr/bin/awk was mawk for a long time with Ubuntu. I remember getting in a heated discussion with GAWK’s maintainer that he should allow a way for [A-Z] to never match lower case letters (it does in some locales) so that we didn’t have to use stuff like [[:upper:]] and [[:lower:]], which do not work in mawk.