This changes all invocations of which tool to command -v tool. The reason for this is that which is, surprisingly, not specified by the POSIX standards. This wouldn't normally matter except, apparently, Arch doesn't install which by default. This leaves us with two options
Add a CHECK_TOOL for the which command
Switch to command -v, which is the basically POSIX equivalent and supported by all shells
This changes all invocations of
which tooltocommand -v tool. The reason for this is thatwhichis, surprisingly, not specified by the POSIX standards. This wouldn't normally matter except, apparently, Arch doesn't installwhichby default. This leaves us with two optionsCHECK_TOOLfor thewhichcommandcommand -v, which is the basically POSIX equivalent and supported by all shells