ENVSUBST(1)

📦
version 1.0 · 11 versions
, in alpine 3.24, arch rolling, nixos 26.05, nixpkgs unstable, ubuntu stonking

💖 ENVSUBST(1) 💖

okay bestie, welcome to the envsubst page from the User Commands section of your manual — she's little, she's powerful, she does ONE thing and she does it flawlessly. no cap.

✨ NAME ✨

envsubst — substitutes environment variables in shell format strings 🫶

🌸 SYNOPSIS 🌸

envsubst [OPTION] [SHELL-FORMAT]

🦋 DESCRIPTION 🦋

Bestie. The whole job description is literally one line and it's iconic: it substitutes the values of environment variables. That's it. That's the girl. 👑

💅 Operation mode:

  • -v, --variables — output the variables occurring in SHELL-FORMAT ✨

🌈 Informative output:

  • -h, --help — display this help and exit 🎀
  • -V, --version — output version information and exit ⭐

so like, in normal operation mode, standard input gets copied straight to standard output, and every reference to an environment variable of the form $VARIABLE or ${VARIABLE} gets swapped out for the corresponding value. the way that works is so satisfying honestly 😭💖

if a SHELL-FORMAT is given, then ONLY those environment variables that are referenced in SHELL-FORMAT get substituted — she's picky, she's selective, she's got boundaries. otherwise, ALL environment variable references occurring in standard input get substituted. everyone eats, no gatekeeping. 🍓

when --variables is used, standard input is ignored (sorry babes, not your moment), and the output consists of the environment variables that are referenced in SHELL-FORMAT, one per line. clean. organized. main character energy. ✨

👑 AUTHOR 👑

Written by Bruno Haible. absolute legend behavior, fr fr 🫶

🙈 REPORTING BUGS 🙈

found a bug? don't suffer in silence bestie, report it in the bug tracker at <https://savannah.gnu.org/projects/gettext> or slide into the inbox at <bug-gettext@gnu.org>. 💌

Copyright © 2003-2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. (yes that's in all caps in the original and yes it means what it means — no safety net, bestie, be careful out there 😭)

🌈 SEE ALSO 🌈

The full documentation for envsubst is maintained as a Texinfo manual. If the info and envsubst programs are properly installed at your site, the command

info envsubst

should give you access to the complete manual. go read her, she's thorough 💜

and that's the whole page, bestie!! this was GNU gettext-runtime 1.0, dated January 2026 — tysm for reading, mwah, stan envsubst, she never misses 💅✨🎀

📦 where this page comes from