Incompatible shell commands

[sebsebmc]

When trying to run this through bash on windows I always get errors in the debug buffer coming from Kakoune trying to execute shell scripts.
There seems to be \bin\sh incompatible (non-POSIX compliant) syntax starting on this line.

I get the following errors after launching Kakoune and switching between insert and normal mode

shell stderr: <<<
/bin/sh: 2: [[: not found
/bin/sh: 4: Syntax error: redirection unexpected
>>>

[danr]

Thanks. There are other bashisms used at other places too, like ${var/pattern/replacement}, but now that there's an interest to change them I might get around to actually doing it :)

[sebsebmc]

Can I ask what the replacements ${ //_/_u} here are doing?
I've managed to replace most of the bashisms but I'm not sure what the purpose of this replacement is.

[danr]

The goal is to replace all newlines with _n, so first underscores are replaced to _u.

This can be done using calling sed instead of bash substitutions.

I'll happily accept PRs that posixify the shell expansions!