fish-shell

name	fish-shell
description	Idiomatic fish shell scripting and config — functions, completions, abbreviations, conf.d, argparse. Use when editing .fish files or anything under ~/.config/fish.

Fish is not bash. Different syntax (test over [[ ]], (cmd) over $(cmd)), string/math builtins, scopes via set -l/-g/-gx/-U, and no &&/|| — use ; and/; or or chained commands.

Repo layout

• Config root: ~/.config/fish/ (chezmoi source: private_dot_config/fish/)
• functions/<name>.fish — autoloaded on first use; filename must match function name
• conf.d/*.fish — sourced at startup; abbreviations, keybindings, env tweaks
• completions/<cmd>.fish — completion definitions
• config.fish — assembled from .chezmoitemplates/fish/*.fish fragments at chezmoi apply time. See chezmoi skill for the assembly model.

Testing in this environment

You're in bash. Run fish via subshell: fish -c "<commands>". New .fish files are picked up automatically by each new subshell after chezmoi apply — no reload needed. Shell side effects can be destructive, so prefer asking the user to test interactive features rather than self-validating.

Jobs to be done

• Write functions — structure, argparse, help text, exit codes, common patterns, worked examples
• Error handling patterns — deeper error/recovery patterns
• Custom logging with logirl — preferred for all structured messages
• Interactive prompts with gum — confirms, inputs, choosers

Fish vs bash quick reference

Bash	Fish
[[ ... ]]	test ...
$(command)	(command)
VAR=value	set VAR value
export VAR=value	set -gx VAR value
command -v cmd	type -q cmd
$((1+2))	math 1+2
${var:-default}	set -q var; or set var default
"${arr[@]}"	$arr
${#var}	string length $var
cmd1 && cmd2	cmd1; and cmd2
cmd1 || cmd2	cmd1; or cmd2
source file	source file or . file

External docs

Fish shell docs — fetch when something isn't covered locally.