Seeing your up alias reminded me of a bash function I setup a while ago also called up. I use it to simulate doing cd .. n number of times. e.g. up 5 would go up 5 directory levels.

up ()
{
    local levels;
    local i;
    [[ -z "$1" ]] && levels=1 || levels="$1";
    for ((i=0; i<levels; i++))
    do
        cd ../;
    done
}

It’s probably the smallest, yet most convenient thing I’ve setup on my machines. Especially so if you work in languages with lots of nested subdirectories (like Java).

Yup, aliases are super useful! One of my most used ones is mkcd; you almost always want to cd into a dir after you make it.

I also like fish’s abbreviations (created through abbr), which are essentially aliases that get expanded when you run them. For example, if I set an abbreviation with abbr -a dkc docker-compose, I can then just type dkc and it will expand it to the full command when I either hit enter or space.