STRING-JOIN(1)

✨ STRING-JOIN 💅 — the fish-shell manual, page 1 of (1)

okay so bestie, buckle up, because this is STRING-JOIN(1), aka the little fish function that smooshes your strings together with a separator and absolutely ate 💖

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🎀 NAME 🎀

string-join — join strings with a delimiter. that's it. that's the whole vibe.

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🦋 SYNOPSIS 🦋

string join [-q | --quiet] [-n | --no-empty] [--] SEP [STRING ...]
string join0 [-q | --quiet] [-n | --no-empty] [--] [STRING ...]

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🌸 DESCRIPTION 🌸

So what it does: it takes your STRING arguments and joins them into one single string, separated by SEP — that's for string join — or by the zero byte (NUL) when you're using string join0. iykyk 😌

Exit status: 0 if at least one join was performed, or 1 otherwise. simple as that, no cap.

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💅 OPTIONS 💅

• -n, --no-empty — leaves empty strings out of the party. like, string join -n + a b "" c would expand to a+b+c and not a+b++c. the "" gets ghosted 👻
• -q, --quiet — doesn't print the strings at all, it just sets the exit status the way we described above. main character energy: shows up, does the job, says nothing 🔥

⚠️ WARNING, and I mean this fr fr: put a -- before your positional arguments so they don't get read as flags. otherwise any string starting with - gets treated as a flag argument, which means your command will most likely just fail 😭 and this hits you even if you're passing a variable that expands to a string like that instead of a literal string. so honestly? if you don't need to append flag arguments at the end of the command, just always use -- and dodge the unwelcome surprises entirely. self-care 💖

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string join0 adds a trailing NUL. this is most useful when you're teaming up with tools that eat NUL-delimited input, like sort -z. obsessed with a collab 🤝

Because Unix uses NUL as the string terminator, passing the output of string join0 as an argument to a command (via a command substitution) won't actually work. 🫠 fish will pass the correct bytes along, but the command won't be able to tell where the argument ends. that's just a limitation of Unix' argument passing — not us, not fish, not your fault. it's giving "blame the ancestors" 💀

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🌈 EXAMPLES 🌈

>_ seq 3 | string join ...
1...2...3

# Give a list of NUL-separated filenames to du (this is a GNU extension)
>_ string join0 file1 file2 file\nwith\nmultiple\nlines | du --files0-from=-

# Just put the strings together without a separator
>_ string join '' a b c
abc

>_ set -l markdown_list '- first' '- second' '- third'
# Strings with leading hyphens (also in variable expansions) are interpreted as flag arguments by default.
>_ string join \n $markdown_list
string join: - first: unknown option
# Use '--' to prevent this.
>_ string join -- \n $markdown_list
- first
- second
- third

see that last one? that's the -- saving your whole life. learn it, love it, use it ⭐

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👑 COPYRIGHT 👑

Copyright: fish-shell developers 🐟

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okay that's the page!! 💜 brought to you by fish-shell developers, version 4.9, dated Sep 08, 2026 — go forth and join your strings responsibly, bestie 🫶✨