brew shellenv is generating no output

[luckman212]

(again, sorry to post here, but the issue tracker is still down)

At some recent point, brew shellenv stopped producing any output on my system. It used to work. I figured out that adding -v produces the expected output:

$ brew shellenv
(nothing)
$ brew -v shellenv
export HOMEBREW_PREFIX="/opt/homebrew";
export HOMEBREW_CELLAR="/opt/homebrew/Cellar";
export HOMEBREW_REPOSITORY="/opt/homebrew";
export HOMEBREW_SHELLENV_PREFIX="/opt/homebrew";
export PATH="/opt/homebrew/bin:/opt/homebrew/sbin${PATH+:$PATH}";
export MANPATH="/opt/homebrew/share/man${MANPATH+:$MANPATH}:";
export INFOPATH="/opt/homebrew/share/info:${INFOPATH:-}";

$ brew update
Already up-to-date.

$ brew doctor
Your system is ready to brew.

$ brew config
HOMEBREW_VERSION: 3.3.5-61-g4c3f325
ORIGIN: https://github.com/Homebrew/brew
HEAD: 4c3f3253473e357c9291e6f10df856ee7019d7a4
Last commit: 15 hours ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 0d8fc4b6b88627d63f7d78207cc69d476794c1a4
Core tap last commit: 38 minutes ago
Core tap branch: master
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_CORE_GIT_REMOTE: https://github.com/Homebrew/homebrew-core
HOMEBREW_EDITOR: /usr/local/bin/subl -w
HOMEBREW_MAKE_JOBS: 8
Homebrew Ruby: 2.6.8 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: octa-core 64-bit arm_firestorm_icestorm
Clang: 13.0.0 build 1300
Git: 2.34.1 => /opt/homebrew/bin/git
Curl: 7.77.0 => /usr/bin/curl
macOS: 12.0.1-arm64
CLT: 13.1.0.0.1.1633545042
Xcode: 13.1
Rosetta 2: false

[Bo98]

Is the brew shellenv variables already exported? It won't output anything if so. Check echo $HOMEBREW_SHELLENV_PREFIX.

[luckman212]

Yes, the variables are already exported. Is this a change? It wasn't the previous behavior as far as I remember.

[Bo98]

This was changed to fix Homebrew/install#559.

[luckman212]

Ah ok. TIL. It might be nice if a message was logged to stderr if this path is hit. Something like an echo 1>&2 "env variables already exported, run with -v to override". This should not break anything.

[carlocab]

I've opened Homebrew/brew#12495 to adjust this behaviour.

[wheelerlaw]

brew -v shellenv no longer prints the output. Was that option removed? I'd like to know what shellenv is printing because I don't have it memorized off the top of my head.

[gromgit]

Explanatory comment in the shellenv script:

To help guarantee idempotence, this command produces no output when Homebrew's `bin` and `sbin` directories are first and second
respectively in your `PATH`.

So if your PATH starts with the Homebrew bin and sbin directories, you can expect no output.

I'd like to know what shellenv is printing because I don't have it memorized off the top of my head.

Per the above comment, you can force output by prepending something to your PATH:

PATH=/dummy:$PATH brew shellenv

[wheelerlaw]

Right, I expected just brew shellenv to not produce anything, but I saw in the original discussion post that they used -v to force the ourput. I tried it out myself and noticed that it didn't work, so I was wondering if at some point it had disappeared.

[gromgit]

As far as I know:

1. brew will move any -v flag that's first in its arguments to the last, so brew -v shellenv is actually evaluated as brew shellenv -v.
2. The shellenv subcommand doesn't take any arguments. The old (Ruby-based?) implementation might have done something with it, but that was replaced by the current Bash implementation in 2018.

Out of curiosity, when was the last time that brew -v shellenv worked for you?

[wheelerlaw]

I had never tried brew -v shellenv until I saw this discussion several days ago.

[warsaw]

I just ran into this problem and nothing I do, nor any of the suggestions above, get brew shellenv to print anything. I'm on Homebrew 4.5.2, macOS 15.5, Apple Silicon. The biggest problem for me was that $MANPATH wasn't getting set, so I just added this manually to my dot files:

export MANPATH="$($brew --prefix)/share/man${MANPATH+:$MANPATH}:";

(I set $brew elsewhere.)

[luckman212]

Not experiencing that on my system. I'm also on 15.5 (arm) and Brew 4.5.2. Both brew shellenv and brew shellenv -v produce the same output:

$ brew shellenv
export HOMEBREW_PREFIX="/opt/homebrew";
export HOMEBREW_CELLAR="/opt/homebrew/Cellar";
export HOMEBREW_REPOSITORY="/opt/homebrew";
PATH="/opt/homebrew/bin:/opt/homebrew/sbin:/Users/luke/.n/bin:/Users/luke/.pipx/bin:/Users/luke/.virtualenvs/bin:/Users/luke/.python/bin:/Users/luke/.orbstack/bin:/Users/luke/.cargo/bin:/Users/luke/go/bin:/Users/luke/Sync/Scripts:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/go/bin:/Applications/Wireshark.app/Contents/MacOS:/Applications/iTerm.app/Contents/Resources/utilities"; export PATH;
[ -z "${MANPATH-}" ] || export MANPATH=":${MANPATH#:}";
export INFOPATH="/opt/homebrew/share/info:${INFOPATH:-}";

What's your brew --config look like?

[gromgit]

nothing I do, nor any of the suggestions above, get brew shellenv to print anything.

As I mentioned in another comment, the only test that brew shellenv does to decide whether to show any output is If your PATH already starts with ${HOMEBREW_PREFIX}/bin:${HOMEBREW_PREFIX}/sbin. If you're already setting that manually before running brew shellenv, then no output will be shown.

What's the output of PATH=/dummy:$PATH brew shellenv?

The biggest problem for me was that $MANPATH wasn't getting set

That's not actually a problem in pretty much all modern *nixes (including macOS), as the widely-used man implementation defaults its search path based on the path that the command being man'd is found. This is why MANPATH= man gfind works even when it shouldn't, because man looks for gfind and finds it in ${HOMEBREW_PREFIX}/bin, so it automatically looks in ${HOMEBREW_PREFIX}/man and ${HOMEBREW_PREFIX}/share/man. You can man manpath to learn more about the default man search path.

If you have a non-empty MANPATH, you can inject the default man search path anywhere you want:

1. Before all other directories: add a colon at the beginning (MANPATH=:${MANPATH})
2. After all other directories: add a colon at the end (MANPATH=${MANPATH}:)
3. Somewhere in the middle: add two colons where you want to insert the default search path (MANPATH=/blah:/foo::/baz:/burp)

This line @luckman212 quoted from brew shellenv:

[ -z "${MANPATH-}" ] || export MANPATH=":${MANPATH#:}";

implements option 1 and correctly does nothing with an empty MANPATH.

[warsaw]

Thanks for the explanation about $MANPATH. I think with that -- and a little testing -- it's clear that brew shellenv is working for me as intended.

One suggestion I'd make is for brew shellenv -d or -v to actual print out what it would do if not for the pre-existing $PATH setting. I think a debug mode would help clear up these confusions.

[warsaw]

What's your brew --config look like?

HOMEBREW_VERSION: 4.5.2
ORIGIN: https://github.com/Homebrew/brew
HEAD: 6f39076b3c2251994419215279d0525ef667fc31
Last commit: 13 days ago
Branch: stable
Core tap JSON: 21 May 19:23 UTC
Core cask tap JSON: 21 May 19:23 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: emacsclient
HOMEBREW_MAKE_JOBS: 8
HOMEBREW_NO_ANALYTICS: set
HOMEBREW_NO_ENV_HINTS: set
Homebrew Ruby: 3.4.3 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.3/bin/ruby
CPU: octa-core 64-bit arm_blizzard_avalanche
Clang: 17.0.0 build 1700
Git: 2.49.0 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.5-arm64
CLT: 16.3.0.0.1.1742442376
Xcode: 16.3
Rosetta 2: false

Could it have something to do with HOMEBREW_NO_ENV_HINTS?