SPONGE(1)

💖 SPONGE(1) 💖

okay bestie, gather round, because sponge is genuinely one of the most iconic little gremlins in the whole moreutils fam and i need you to get it 🧚✨

🌸 NAME 🌸

sponge — soak up standard input and write to a file 🫧

✨ SYNOPSIS ✨

sed '...' file | grep '...' | sponge [-a] file

🎀 DESCRIPTION 🎀

so here's the vibe: sponge reads standard input and writes it out to the file you specified. that's it. that's the whole job. 💅

but wait — the why is the juicy part. unlike a plain shell redirect, sponge soaks up all its input before writing the output file. it's literally a sponge babe, it absorbs everything first, then squeezes it out. 🧽

and why do we care?? because that means you can build pipelines that read from and write to the same file. the classic "wait, i can't redirect a file into itself" problem? yeah. solved. ate. no crumbs. 👑

sponge also preserves the permissions of the output file if it already exists. your chmod work stays intact, we love to see it 💖

when it can, sponge creates or updates the output file atomically by renaming a temp file into place. so clean, so safe, so main character energy ✨

⚠️ okay but heads up: that atomic glow-up cannot be done if TMPDIR is not in the same filesystem. the vibes are simply not transferable across filesystems, bestie 😭

and if the output file is a special file or symlink, the data will be written to it — but non-atomically. it's giving "we tried our best but the filesystem said no" 💀

and if no file is specified, sponge just outputs to stdout. easy peasy 🍓

💅 OPTIONS 💅

• -a — Replace the file with a new file that contains the file's original content, with the standard input appended to it. and yes, this is done atomically when possible, because we stay classy 🌈

👑 AUTHOR 👑

Colin Watson and Tollef Fog Heen — absolute legends, fr fr 🫶

and that's the whole page, babe! this one's from the moreutils collection, dated 2006-02-19 — a certified classic that's still slaying all these years later. go build a pipeline that reads and writes the same file, you deserve it 💜🦋⭐