Previously this didn't work:
$ cd -- /usr
Invalid path '--'
This path fixes this issue and removes the unnecessary else
branch because we're already using realpath() later on to resolve
relative paths.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This fixes `fg` and `bg` causing the shell to go into an infinite loop
of trying to `waitpid` until some current job changes state.
a.k.a. "Fix Shell backgrounding, yet again!" :P
Non-interactive shells (i.e. when running scripts) do not need this
functionality, so they are a boatload of wasted time.
This significantly reduces the script startup and shutdown times when
there are lots of executables in PATH or lots of entries in the history.
