The Living Thing / Notebooks :

The Fish shell

Finally, a command line shell that thinks that the problem is not you

Not the aquatic creature, but rather the command-line doohickey, which is not as shit as the other ones. I’m gradually transitioning to fish, after accidentally losing a lot of precious data due to a quirk in bash syntax. Long boring story. It’s time for new, exciting, different stupid errors.

fish has a strong fanbase and an opinionated design. If you dislike those opinions, at least you might appreciate it has a healthy degree of sarcasm in its opinions, which sarcasm is sorely absent from the drearily earnest nerdview of your typical gnu.org project. You might also hold that having some kind of opinion is better than the design-by-accumulation-of-cruft which structures traditional command-line shells.

Pro tips

modifying the search PATH

Adding a path? Say it’s /usr/local/bin. Put

set -gx PATH /usr/local/bin $PATH

in ~/.config/fish/config.fish.

Removing a path?

set -gx PATH (string match -v /usr/local/bin $PATH)

OR

set -U fish_user_paths /usr/local/bin $fish_user_paths

TODO: explain the differenece between $PATH and $fish_user_path which will depend upon me working out how the content of $PATH magically replenishes itself.

Python environments

virtualenv

if you are still using virtualenv on python you will need virtualfish to replace python’s virtualenvwrapper.sh. Or switch to native python3 venv, which is more or less the same thing but works better, but doesn’t support python2. But if you need to support python 2 at this stage it’s because you are in some weird enterprise environment with horrid legacy software, so hopefully you can farm this problem out to the tech support team?

Using anaconda python

You need to do some extra setup to use conda with fish. Specifically, add the line

source ~/anaconda3/etc/fish/conf.d/conda.fish

into ~/.config/fish/config.fish.

(Replace ~/anaconda3/ with the output of conda info --root if you used a nonstandard install location)

Now you can activate an anaconda environemnt, e.g. the default base environment:

conda activate base

Modifying any settings with GUI

fish_config

Vars, expansions

for file in (ls *.html)
    mv $file (basename $file .html).txt
end

For loops

#!/bin/fish
while true
    echo "Loop forever"
end

Temporary variable setting uses env

env FOO=BAR baz.sh

Execute the second command if the first succeeded

The commmand you want is and, which is hard to google for

../bin/something.sh foo; and cp foo ~/Dropbox/

aliases, custom commands

command, alias, or abbr?

Command allows overwriting a command. Alias makes an alias, but is lacking autocomplete. Abbr makes a sort of alias that will expand out and support autocomplete.