SC2230

which is non-standard. Use builtin 'command -v' instead.

Problematic code:

which grep

Correct code:

command -v grep

Rationale:

which is a non-standard, external tool that locates an executable in PATH. command -v is a POSIX standard builtin, which uses the same lookup mechanism that the shell itself would.

Exceptions:

None

Caveats:

With BASH 5.0.7 (via homebrew on macOS 10.13.6), command -v appears to take multiple parameters:

# grep is in /usr/bin/grep
# foobar is not in path
#
$ command -v -- grep foobar; echo $?
0

but succeeds (with exit code 0) if any command exists. In the above example, it should have failed and exited with 1 unless all commands exist.

An alternative is:

$ hash <file1> <file2>

Which observes the standard behaviour of failures.

Related resources:

• Check if a program exists from a Bash script on StackOverflow.