brain initiation

20231011101006-fish.org

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+:PROPERTIES:
+:ID:       af92f7a3-705c-491e-955e-2f04206da220
+:END:
+#+title:  fish
+#+filetags: :basics:system:linux:
+
+fish is the *friendly interactive shell*. A [[id:b6d24dd6-285f-4c03-883c-dc77b78c652a][shell]]  like bash that mimmicks a [[id:d71414fc-349c-4763-a703-9f7092fc90d6][command-line]] and is able to interact with [[id:5fada795-19a3-4ba6-97c0-0b70bd728a2f][Linux]].  Fish is highly customizable.  To Customize the fish shell you have to change its configuration at  [[~/.config/fish/config.fish]] or via the shell command ~fishconf~.  for a shell to work in a [[id:a08570b0-8fe8-45a8-8f60-e45ea6b31a34][GUI]] system it needs a [[id:5ddb50eb-4257-44cb-9193-1606b348e886][terminal emulator]] to run in.  One of those emulated [[id:4c3c3777-af52-4cde-8d9b-f356701b94c9][terminals]] is [[id:b65b3f3a-e0a3-49ca-9005-5a1055c07cdf][kitty]]. 
+
+Fish has "search as you type" automatic suggestions based on history and current directory. This is essentially like Bash's ~Ctrl+R~ history search, but because it is always on instead of being a separate mode, the user gets continuous feedback while writing the command line, and can select suggestions with the arrow keys, or as in Bash, press Tab ↹ for a tab completion instead. Tab-completion is feature-rich and has expanding file paths (with wildcards and brace expansion), variables, and many command specific completions. Command-specific completions, including options with descriptions, can to some extent be generated from the commands' man pages.
+
+Fish prefers features as commands rather than syntax. This makes features discoverable in terms of commands with options and help texts. Functions can also carry a human readable description. A special help command gives access to all the fish documentation in the user's web browser.
+
+* Universal Variables
+Fish has a feature known as universal variables, which allow a user to permanently assign a value to a variable across all the user's running fish shells. The variable value is remembered across logouts and reboots, and updates are immediately propagated to all running shells.
+#+begin_src bash
+  # This will make emacs the default text editor. The '--universal' (or '-U') tells fish to
+# make this a universal variable.
+set --universal EDITOR emacs
+
+# This command will make the current working directory part of the fish
+# prompt turn blue on all running fish instances.
+set --universal fish_color_cwd blue
+#+end_src
+