shell: use /usr/bin/env instead of absolute paths
This commit changes the shebang in all shell scripts from absolute
paths (such as /bin/bash
or /usr/bin/python3
) to the /usr/bin/env
binary with the accompanying interpreter as it's argument.
The reason for this are as follows:
- NixOS cannot work with absolute paths
- BSD systems install their packages in /usr/local/bin