Bash, just because everything else already uses it. That and bashisms have infected nearly all of my scripts as I clumsily bump into the limitations of POSIX string manipulation.
I have found some very fun things with sed branching patterns as a result of these limitations though...
https://www.gnu.org/software/sed/manual/html_node/Branching-and-flow-control.html
Fuck it. Gun it at the brick wall. Jerry's rigging up an emergency break as we speak. Don't mind that the last piece to said break may be missing.
Man who will probably die before we hit the wall