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Title: Playing with a new shell: fish |
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Author: Solène |
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Date: 05 September 2021 |
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Tags: openbsd shell |
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Description: |
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# Introduction |
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Today I'll introduce you to the interactive shell fish. Usually, Linux |
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distributions ships bash (which can be a hidden dash, a limited shell), |
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MacOS is providing zsh and OpenBSD ksh. There are other shells around |
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and fish is one of them. |
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But fish is not like the others. |
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fish shell project website |
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# What make it special? |
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Here is a list of biggest changes: |
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* suggested input based on commands available |
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* suggested input based on history (even related to the current |
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directory you are in!) |
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* not POSIX compatible (the usual shell syntax won't work) |
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* command completion works out of the box (no need for extensions like |
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"ohmyzsh") |
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* interconnected processes: updating a variable can be done into every |
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opened shells |
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Asciinema recording showing history features and also fzf integration |
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# Making history more powerful with fzf |
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fzf is a simple utility for searching data among a file (the history |
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file in that case) in fuzzy mode, meaning in not a strict matching, on |
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OpenBSD I use the following configuration file in |
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~/.config/fish/config.fish to make fzf active. |
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When pressing ctrl+r with some history available, you can type any |
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words you can think about an old command like "ssh bar" and it should |
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return "ssh foobar" if it exists. |
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```fish config sample |
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source /usr/local/share/fish/functions/fzf-key-bindings.fish |
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fzf_key_bindings |
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``` |
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fzf is absolutely not related to fish, it can certainly be used in some |
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other shells. |
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github: fzf project |
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# Tips |
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## Disable caret character for redirecting to stderr |
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The defaults works pretty well but as I said before, fish is not POSIX |
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compatible, meaning some habits must be changed. By default, ^ |
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character like in "grep ^foobar" is the equivalent of 2> which is very |
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misleading. |
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```fish config sample |
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# make typing ^ actually inserting a "^" and not stderr redirect |
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set -U fish_features stderr-nocaret qmark-noglob |
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``` |
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## Web GUI for customizing your shell |
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If you want to change behaviors or colors of your shell, just type |
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"fish_config" while in a shell fish, it will run a local web server and |
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open your web browser. |
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## Validating a suggestion |
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When you type a command and you see more text suggested as you type the |
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command you can press ctrl+e to validate the suggestion. If you don't |
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care about the suggestion, continue typing your command. |
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## Get the return value of latest command |
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In fish, you want to read $status and not $? , that variable doesn't |
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exist in fish. |
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## Syntax changes |
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Because it's not always easy to find what changed and how, here is a |
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simple reminder that should cover most of your needs: |
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* loops (no do keyword, ends with end): for i in 1 2 3 ; echo $i ; end |
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* condition (no then, ends with end): if something ; echo true ; end |
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* inline command (no dollar sign): (date +%s) |
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* export a variable: set -x EDITOR kak |
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* return value of last command: $status |
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# Conclusion |
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I love this shell. I've been using the shell that come with my system |
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since forever, and a few months ago I wanted to try something |
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different, it felt weird at first but over time I found it very |
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convenient, especially for git commands or daily tasks, suggesting me |
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exactly the command I wanted to type in that exact directory. |
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Obviously, as the usual syntax changes, it may not please everyone and |
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it's totally fine. |
