While creating set of bash_completion rules for mc-tool, I read some other rule files to see how things are done. I happened to spot some useful functions from git's completion, mainly __git_ps1, which prints the name of the current branch.
Having the name of the current branch can save some mistakes every now and then, and with environment variable GIT_PS1_SHOWDIRTYSTATE you can even make it show if there are non-staged and/or non-committed changes in your tree.
This is how I used it:
By default the output of __git_ps1 is " (name-of-branch)", or "" if current directory does not belong to a git tree. The format string can be given on command line, like " (%s)".
The current version seems to have a small glitch that causes it to print give (unknown) for home directory, if you use git global settings.
While mixing hobby and work development on the same machine, I've every now and then longed for a way to set environment variables depending on the current directory. Up to now had I been too lazy to do anything about it, but finally did it.
What the snippet does, it finds all current user owned .env files from current directory and it's parent directories, checks if the topmost has changed and if it has, reads them all in reverse order. If home directory was not a parent of current directory, the ~/.env is read before others.
If you want this too, look at the code. Include these in your .bashrc, and you should be good to go.
Examples of environment variables I've found useful are DEB_EMAIL and DEB_FULLNAME used by dpkg tools and the equivalents in git world, GIT_COMMITTER_EMAIL, GIT_COMMITTER_NAME.