The "which" utility is not guaranteed to be installed either, and if it is, its behavior is not portable either. This means that when rdfind / pre-commit are installed, the `which` check will report a fatal error because the which tool did not exist and the shell returned a nonzero status when attempting to fork+exec. If it did exist, it might not be an implementation of `which` that returns nonzero when commands do not exist. Conversely, the "command -v" shell builtin is required to exist in all POSIX 2008 compliant shells, and is thus guaranteed to work everywhere. For some in-depth discussions on the topic, see: - https://mywiki.wooledge.org/BashFAQ/081 - https://unix.stackexchange.com/questions/85249/why-not-use-which-what-to-use-then/85250#85250 Examples of open-source shells likely to be installed as /bin/sh on Linux, which implement the 15-year-old standard: ash, bash, busybox, dash, ksh, mksh and zsh. A side benefit of using the POSIX portable option is that it requires neither an external disk executable, nor (because unlike "which", the exit code is reliable) a subshell fork. This therefore represents a mild speedup. Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>