Convert scripts to POSIX sh for portability

[trevarj]

This would be ideal, since I broke backwards compatibility in the refactoring of ton, even with old Bash versions (like on MacOS).

It shouldn't be too difficult...just need to set the shebang to #!/bin/sh and let shellcheck show all the bashisms, then get grinding (painful?). I think it's mostly array stuff which can be replaced with awk one liners.