• General Usage
• Scripting
• Working with find
• Searching For Patterns the_platinum_searcher
• Working with lambda theme
• Working with jobs
  • Moving a jobs to and from foreground to background
• Working with PATHs
• Working with aliases
• Random Hacky shit
• Working with Functions
• Working with abbreviations
• Frameworks
  • omf
• fzf
• Profiling Benchmarking Performance
• BASH Notes
• Useful Links
• Troubleshooting
• TODOs

Presently, Sep 23, 2018, fish does not support loading with no configuration, or disabling configuration files or directories. To get a status of when this might be possible see this

To compile fish shell from source using homebrew

cd $HOME/Library/Caches/Homebrew/fish--git \
git pull origin master \
brew reinstall fish --verbose --HEAD \
brew upgrade fish --verbose --HEAD \
brew link -f fish

use either reinstall or upgrade, but not both

Contrast BASH fish does not play well with using brace expansion when working with ranges. That said, fish provides index range expasion which works well as a substitue to BASH's brace expansion. 👍

To perform an action in BASH on a range of values

rm -rf /path/to/mr-fancy-dir-{1..42}

To perform the above expression in fish, ie. remove a range of directories or values

rm -rif (ls /path/to/mr-fancy-dir)[1..42]

The above expression should get the same mileage as bash. 🚗

To iterate over all the files in a directory and make a change to all files, ie. change all files ending in .jpg to .jpeg

for i in *.jpg; mv -iv $i (basename $i .jpg).jpeg; end

The above command will change all .jpg files to .jpgeg in the current working directory.

To prepend a sequential numerical value to a directory of files based on their creation date using fish shell.

fish does not evaluate expressions the same way bash or other POSIX shells do.

1. To list all the files in a directory from oldest to newest, ie. oldest at the top of the list, and newest at the bottom of the list.

ls -tr

The above command will list just the basename for the files in a directory and put the oldest file at the top of the outputted list, and new file at the bottom of the list. The -r flag reverses the order. 👍

To iterate over the file in a directory a while loop can be used.

set n 0
ls -tr | while read fname
 set n (math $n + 1)
 mv -iv $fname (printf '%02d%s\n' $n $fname)
end

The above command will iterate over the entire list of files in the directory and increment the variable n for each file, and the printf command will prepend a two digit number to the file name starting with 01 and should sequential number each file based on it's creation date.

Putting the below line at the top of a script file will exit the script if there are any errors.

set -e

☣️ Highly opinionated statement below

Fish follows a philsophy of avoding special syntax for things that can be expressed as a command, ie. the difference in BASH and fish handle process substitution.

To record a terminal session that doesn't record time between key presses or commands but rather records, ie waits for input, but doesn't record the time between input, thus allowing for terse terminal session recordings. 👍 there is the script command.

macOS uses the BSD derivative of script

To record a terminal session using script on macOS

script -r /path/to/mr-fancy-script-recording.log

To playback the script recording using script

script -p /path/to/mr-fancy-script-recording.log

To debug and direct all output from a command run via a fish shell

fish -d 3 /path/to/mr_buggy.fish > /path/to/all/output ^&1

More detailed info on redirection with the fish shell see

To create four new files using brace expansion

touch {macOS,windows,linux,freebsd}

To display the know tab completions for a command within fish shell.

fish_update_completions

The above command, fish_update_completions requires Python >= 3.x

fish_update_completions should be run periodically ie. with a cron job to stay current with completions.

then to display a list of completions for a command, ie.

<command> -

the tab key must be pressed after inserting the - to display a list of completions.

To prevent fish from stair stepping emojis when using a prompt that has the right prompt enabled

set -gx fish_emoji_width 2

To reload the fish shell environment without closing the current shell session, ie. closing a tab / window in iTerm2.

The below command is useful when editing files such as config.fish and want to see the changes applied in the current session.

exec fish

To see if the current shell / terminal combination can support italics

echo -e "\e[3m foo \e[23m"

The above command should print foo

To remove the executable bits from files with various extensions

find . \( -iname '*.png' -o -iname '*.jpg' \) -exec chmod 644 '{}' \;

To search for a pattern within all text / source code files within the current working directory

pt [mr-fancy-expression-to-search-for]

The above command is quite useful for finding syntax errors that are scattered through a directory structure, and the specific file / line is not specified within standard error output.

The idea 💡 display a "number in exponential notation" when a subshell is invoked, ie. provide some form / sort of feedback to let the user know if their within a nested shell.

How to display a number to a power, ie. 2 to the 2^2 power?

Numbers represented as exponents on a computer screen are referred to as superscript.

• Mapping codepoints to Unicode encoding form
• Unicode.org Unicode Subscripts & Superscripts
• console codes

To input a specific Unicode character by its four digit sequence using the Emoji & Symbols contextual menu in macOS

1. Bring up the Emoji & Symbols macOS native contextual menu, and to input a-superscript 2 input u+00b2 into the menu, and a superscript 2 should become selectable within the context menu.

1. If a job is running the foreground of an interactive shell, thus not allowing the user to interact with the shell, the process can be suspended with control+z
2. Then the process can be moved to the background with bg command.

The above bg command will unsuspend the process and resume its operation.

3. To keep the process running after the interactive shell session has been exited from, run disown

If the process is running the background and needs to be moved to the foreground of an interactive shell session use the fg command.

To display a list of PATHs on the system

pretty-path

The above command is dependent on the prett-path fish function being setup in the fish shell environment

To erase a path from the outputted list

set -e PATH[<the_number_of_the_path_entry_to_delete>]

Example

set -e PATH[3]

Credit 💳

An alternative way to remove a path entry from $PATH

set PATH (string match -v /some/path/entry $PATH)

If modifying PATH entries in stored in 001_load_paths.fish then a couple of steps will be required to update all interactive fish shell instances.

1. Remove unecessary PATH entries from 001_load_paths.fish
2. Remove paths from fish using the path_remove fish function

path_remove only needs to be invoked once in a single interactive fish shell.

3. If running a bunch of different interactive fish shell instances within tmux, save the configuration, then detach from tmux, and kill the detached session.
4. Start a new tmux session, restore tmux from saved session, all interactive fish shells have the updated path entries.

To print a list of aliases for the current fish session

alias

To remove an alias 💳

functions -e <name_of_alias>

Example,

functions -e less

Created the below alias on both *nix and macOS to allow tmux to find fish stored in a centeral location.

ln -sf (which fish) /bin/fish

To print the description for a custom function

functions --details -v <name_of_custom_function>

Example

╭─capin at rogue in /opt/Code/dotfiles (master ✔)
╰─λ functions --details -v toggle_homebrew_python_path 121 < 14:18:21
/Users/capin/.config/fish/functions/toggle_homebrew_python_path.fish
autoloaded
1
scope-shadowing
toggle homebrew python 🐍

⚠️ With recent version of fish abbreviations are stored as universal variables, that said all universal variables can be edited by modifying ~/config/fish/fish_universal_variables file, as opposed to removing manually using abbr -e [mr-fancy-abbr].

To list installed packages / themes

omf list

To update a package or theme, ie. neolambda

omf update neolambda

To update the oh-my-fish framework itself

omf update omf

OMF oh-my-fish stores the contents of a plugin / package in

$HOME/.local/share/omf/pkg

A guide for creating a theme / plugin for omf can be found here

• fzf - is command line fuzzy finder that be used from the CLI or from within a text editor such as vim to quickly find files, a la spotlight search.

fzf is written in go and is asynchronous out of the box.

To search through the command history control + r

To search from files from within the current directory control + t

🚨 The below is a hacky solution to get fzf working with different brew prefixes

To get the brew prefix

echo (brew --prefix)

• Create the below directory structure with a symlink on *nix to mimic that of macOS

/usr/local/opt/fzf/shell/key-bindings.fish

• Then symlink /usr/local/opt/fzf/shell/key-bindings.fish to ~/.config/fish/functions/key-bindings.fish

Unlike other shells fish does not have a builtin time command, so rely on using the systems time command; usually located at /usr/bin/time

To get a ballpark figure of how long a process takes to launch on a *nix system

/usr/bin/time -v fish exit

on macOS

/usr/bin/time -l fish -c exit

As of April 10, 2018 fish v2.7.1 with my current dotfiles is taking ~ 0.88 seconds to launch an interactive shell session. 🙄

Fish also has a builtin command flag of -p or --profile that writes profiling information to PROFILE_FILE environment variable.

A useful command for profiling fish

fish --profile /tmp/fish.prof -c 'true'; sort -nk1 /tmp/fish.prof | tail -n 20

A more verbose profiling solution for measure launch time of fish

fish -p /path/to/mr-fancy-profile.txt -c exit

The unit of measurement in mr-fancy-profile.txt are microseconds.

To unset an environment variable in BASH

unset [env-var]

Ex

unset HOST_CC

To list all exported variables and functions

export -p

aliases should be placed within $HOME/.bashrc or $HOME/.bash_aliases.

Make sure bash sources the .bash_aliases file if it is used.

To add an alias for BASH place the custom shell alias within the ~/.bashrc file.

To add a custom PATH to the BASH environment, ie. /mr/fancy/pants/path/ add it to $HOME/.bashrc ie.

PATH=/mr/fancy/pants/path:$PATH

To lint, ie. check a bash script for syntax errors

bash -n mr-fancy-bash-script.sh

To use a no-op instruction with BASH

if [ `id -un` = capin ] ; then
 echo "yup its me"
elif [ `id -un` = root ] ; then
 : # `:` is the no-op instruction
else # everyone else
 echo "erbody else"
fi

To test a file / directory is writeable use [ -w within a shell script.

To pad a directory of files with 000 etc, so listing the files, will print the files in a more sane order, useful for viewing files in "correct" order.

1. pad all existing files with a set of zeros

for f in mr-fancy-file[0-9]*; do mv $f `printf mr-fancy-file%05d ${f#mr-fancy-file}`; done

OPTIONAL if desired reapply extension to modified files

2. reapply extension

for f in *; do mv "$f" "f.mr-fancy-file-extension"; done

If bass is installed using a fish plugin manager, simple BASH scripts be run from within fish, ie.

bash export X=3

will properly set the env var using fish grammar. 👍

Executing a programs through BASH as a fish shell function, use

bash -c '$HOME/path/to/mr-fancy-program "$@"' dummy $argv

see

• Hyperpolyglot - comparing shell syntax
• Useful nuggets about fish shell from the Arch 🏹 wiki
• My personal journey to troubleshooting a busted config.fish
• Great 👌 writeup for setting up fish shell on macOS
• GitHub - fish-shell cookbook
• StackOverflow - Comparing fish-shell to BASH
• Great 👍 explanation of bracketed paste

Fish provides a bind builtin / command to work with key bindings when using an interactive fish shell session.

To paste text on the CLI using fish use control + v and text stored in the system clipoard should be pasted at the prompt.

To list all the different modes fish provides when working with key bindings

bind -L

should output something like

default
paste

• better organize the notes about using bass with fish shell, ie. don't put them in with BASH Notes