I recently received a Steam Deck and I love it!
I also planning to use it for development. On my PC I get used to Fish shell and usually use it instead of Bash. I can install it on Steam Deck and set it to the default shell, but after a system update it will be wiped. I can create a script and run it after each update, will I be able to login if my user points to /usr/bin/fish that doesn’t exist in the system?..
I think you can install fish from the discover store, which will persist between updates. You may need to also update its permissions through flatseal so that it has full file system access.
Some other options for packages are to install them through nix or distrobox. There’s also a set of commands for installing a package locally, but I would have to look it up. It involves setting a temporary cache directory, downloading the package there without installing it, and then installing the contents of cache to a folder in user-space.
It’s not on flathub, so it won’t show up in discover.
Generally, it doesn’t have command line programs, just fyi ones