Use 'command -v' over 'which' to find a program's executable

One thing that came to me as news is that the command which - which is the de-facto tool to find the path of an executable - is not POSIX compliant. The recent [Debian which hunt] brought it to my attention. The POSIX-compliant way of finding an executable program is command -v, which is usually built into most of the shells. So, instead of doing this: Do this: [debian which hunt]: https://lwn.net/Articles/874049/