fish(1) manpage: -i/--interactive flag

Metadata

Field	Value
Institute	Molodetz Institute — Research & Retrieval Division
Subject	shell-multiplexer-auto-attach
Document type	Source Dossier
Tier	1
Source title	FISH(1)
Source URL	https://man.archlinux.org/man/fish.1.en
Source publisher / author	fish-shell project, mirrored by the Arch Linux manpage service
Source type	vendor docs
Source date (published)	Unknown — not stated
Date researched	2026-10-10
Researched by	tai (agent), model: Claude Sonnet 5, on behalf of retoor
Research method	web search synthesis
Confidence	High
Status	Active

Summary

fish's own command-line options include -i/--interactive, documented (current wording) as forcing interactive mode regardless of how fish was actually started — the direct fish analogue of bash's own -i flag, confirming fish can be spawned the same way (fish -i) that the existing bash/zsh integration-test fixtures already spawn bash -i/zsh -i.

Key findings

-i/--interactive sits alongside -l/--login, -n/--no-execute, and -P/--private in fish's own options list — a first-class, stable flag, not a hidden or undocumented one.
Current wording (Arch, Debian trixie, openSUSE Tumbleweed mirrors) is terse: "the shell is interactive" / forces interactive mode. Older mirrors (Ubuntu 20.04 focal, an older linux.die.net copy) use slightly different directive-style wording ("specify that fish is to run in interactive mode") describing the same behavior — a wording change across fish/doc versions, not a behavior change.
This directly justifies using fish -i to spawn real fish processes in the FishInstallAndAutoWrapTest/FishAntiRecursionTest/FishTmuxActiveSkipTest integration tests in tests/bashrc.py, exactly mirroring how the existing bash/zsh tests spawn bash -i/zsh -i.

Pros / strengths

Confirmed across multiple independent manpage mirrors (Arch, Debian, openSUSE, plus older Ubuntu/linux.die.net copies) with consistent meaning despite wording differences — high confidence this flag behaves as expected on any fish a real test container would have installed.

Cons / limitations / caveats

None identified beyond the wording-only discrepancy already noted; doesn't change the behavior being relied on.

Relevance to tai

Directly justified the test design in tests/bashrc.py's _ShellPlexerHookTestBase._spawn_shell(["-i"], ...) calls for the fish test classes — proof that fish -i is a real, stable, documented way to force a real interactive fish process for the end-to-end auto-wrap/anti-recursion/tmux-skip tests, run for real against the fish binary installed in tests/docker/Dockerfile.

Changelog

Date	Change
2026-10-10	Initial dossier created.

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