---
title: "Fish Shell 4.6 — Introduction & Setup"
aliases: [fish-shell, fish-intro, fish-setup]
tags: [fish, shell, terminal, dotfiles, cli]
sources: [raw/Introduction — fish-shell 4.6.0 documentation.md]
created: 2026-04-17
updated: 2026-04-17
---

## What is Fish?

Fish (**f**riendly **i**nteractive **sh**ell) is a shell focused on usability and interactive use. It works out-of-the-box without configuration.

**Headline features:**
- Syntax highlighting, autosuggestions, tab completion with navigable/filterable lists
- No config required — ready immediately after install
- Easy scripting with a clean, learnable syntax

## Starting & Exiting

```fish
fish        # start a fish session inside another shell
exit        # end the session
```

## Making Fish Your Default Shell

**Option A — terminal emulator setting** (safest): point your terminal (WezTerm, Kitty, iTerm2) to `/usr/local/bin/fish` directly in its config.

**Option B — login shell** (riskier, see warning below):

```bash
command -v fish | sudo tee -a /etc/shells   # register fish
chsh -s "$(command -v fish)"                # set as login shell
```

> [!warning] Login shell caveat
> Some Linux distros require the login shell to be Bourne-compatible and source `/etc/profile`. Fish is not Bourne-compatible — this can break PATH and other env vars. Prefer the terminal emulator approach on Linux.

## Configuration Files

| File | Purpose |
|------|---------|
| `~/.config/fish/config.fish` | Main config — runs every shell startup |
| `~/.config/fish/conf.d/*.fish` | Auto-sourced before `config.fish` |

Use guards to scope behavior:

```fish
if status --is-interactive
    # interactive-only setup (prompt, aliases, etc.)
end

if status --is-login
    set -gx PATH $PATH ~/linux/bin
end
```

Prefer `fish_add_path` over manual PATH manipulation — it deduplicates automatically:

```fish
fish_add_path ~/linux/bin
```

## Shebang Line for Fish Scripts

```fish
#!/usr/bin/env fish
echo Hello from fish $version
```

Use `env fish` (not a hardcoded path) so the script works regardless of where fish is installed. The shebang is only needed when executing a script directly — not when running with `fish /path/to/script`.

## Exit Event Handler

```fish
function on_exit --on-event fish_exit
    echo fish is now exiting
end
```

## Inspecting Your Config Changes

```fish
fish_delta   # shows what you changed from fish's defaults
```

## Key Takeaways

- Fish is **batteries-included**: syntax highlighting, autosuggestions, and completions work with zero config
- **Don't set fish as login shell on Linux** unless you know your distro supports it — use terminal emulator config instead
- Config lives in `~/.config/fish/config.fish`; modular snippets go in `conf.d/`
- Use `fish_add_path` instead of manually editing `$PATH`
- Script shebangs should use `#!/usr/bin/env fish` for portability
- `fish_delta` reveals your customizations vs defaults

## Related

- [[wiki/dotfiles/linux-terminal-ricing|Linux Terminal Ricing]] — Kitty + Fish + Tide full setup guide
- [[wiki/dotfiles/terminal-cheatsheet|Terminal Cheatsheet]] — daily stack reference with fish/zsh
- [[wiki/dotfiles/wezterm-config|WezTerm Config]] — set fish as the default program in WezTerm

## Sources

- `raw/Introduction — fish-shell 4.6.0 documentation.md` (fishshell.com/docs/current/index.html)