Hi everyone, I wrote a script which may end up as part of a package on various Linux and BSD flavors, and I have hit the problem of getting the shebang working everywhere. You might know that Python is installed in different locations, with the binary having different names (for example python sometimes points to python2.x, sometimes to python3.x etc.).
Currently my code is compatible with both Python 2 and 3, but to keep things simple I'd rather use only one of them, probably 3. What is the correct way to write a shebang on OpenBSD? I thought that the following would work on most Unixes: #!/usr/bin/env python3 or even this, with the risk of not knowing if it points to 2 or 3: #!/usr/bin/env python Unfortunately when I install the python3 package with pkg_add (actually 3.5) on OpenBSD, no symlink is created from python3 to 3.5, so this fails. I do not want to add a hard dependency on specifically 3.5 in the shebang of my script, since it may become obsolete in a couple of years, and it may be incompatible with other OSes which might not have 3.5, but maybe 3.4 or 3.6. Should I instead use an installation-time script that generates the right shebang? How about a wrapper shell script which searches for a python executable and then calls it with a path to the script? For example the following polyglot script would work: #!/bin/sh ''''which python3 >/dev/null 2>&1 && exec python3 "$0" "$@" # ''' ''''which python3.6 >/dev/null 2>&1 && exec python3.6 "$0" "$@" # ''' ''''which python3.5 >/dev/null 2>&1 && exec python3.5 "$0" "$@" # ''' ''''which python3.4 >/dev/null 2>&1 && exec python3.4 "$0" "$@" # ''' ''''exec echo "fatal: cannot find python3 binary" # ''' All these methods seem quite convoluted for doing something so simple. Please let me know what you think. Thanks in advance for your advice. Ovidiu
