Fish is really great for using it in your terminal. Autocompletion, fuzzy matching, and so on, are amazing.

Unfortunately, although it is fully scriptable, writing scripts in Fish feels a little clunky at times. For example, I wanted to test if $dest exists, and if not, whether $src is newer than $dest. Since there are no && or ||, parentheses are used for command substitution, and the Fish version of "test" has no -nt to check if a file is newer, I have to do this:

    if begin; not command test -f $dest; end; or begin; command test $src -nt $dest; end
        # do something
    end