Change shebang to /bin/bash

[alexamirante]

In Ubuntu the default shell points to dash rather than bash. As such, this substitution (line 375):

    GUEST_IFNAME=${GUEST_IFNAME:0:15}

returns an error as that syntax is not supported by dash. Setting the shebang do /bin/bash fixes this.

[jpetazzo]

Good point, thanks for catching this!

[yoursunny]

I have been using this script (specifically pipework --wait subcommand) in Alpine-based containers, where the default shell is ash and there's no bash command. I'd suggest reverting this change and rewriting the ${GUEST_IFNAME:0:15} with awk or similar utility.

[ClausKlein]

I use a busybox container without bash too

[jpetazzo]

For now, my recommendation would be to add bash to your container; but if someone wants to replace the ${GUEST_IFNAME:0:15} with a call to cut, I'll be happy to receive a PR! 👍