Remove bashisms in src/bin shell scripts

[sagetrac-tmonteil]

It seems to increase portability, see e.g. #17513.

Component: scripts

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/17699

[jdemeyer]

comment:1

We have been assuming bash for a very long time. Removing bashisms would require replacing those scripts by more complicated code, giving more chances of breakage.

And if you stop assuming bash as shell, you have to test that things works on all shells. Again giving more chances of breakage.

Proposal: close as "wontfix".

[jdemeyer]

Reviewer: Jeroen Demeyer

[a-andre]

comment:2

As pointed out by Volker in #15642 comment:13 and [1]

Python is a requirement. Sooner or later Sage won't build without Python

so the shell scripts could be replaced by python scripts as it is done in #15642.

[1] https://groups.google.com/forum/#!topic/sage-devel/akds04MBQYg