gometalinterがhomebrewで入れられるようになってたので、homebrewに切り替えました。
（ここ本題じゃない）
その際に、想定外の動作が起きました。（いい意味で）

brew tap alecthomas/homebrew-tap && brew install gometalinter

今まで、そうだったので下記のように動くものと想定してました

予想

Updating Homebrew...
==> Auto-updated Homebrew!
Updated 4 taps (homebrew/core, homebrew/cask, homebrew/bundle and homebrew/cask-fonts).
==> New Formulae
(省略)
==> Updated Formulae
(省略)

==> Tapping alecthomas/tap
Cloning into '/usr/local/Homebrew/Library/Taps/alecthomas/homebrew-tap'...
remote: Enumerating objects: 4, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 4 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (4/4), done.
Tapped 1 formula (26 files, 25.4KB).
Updating Homebrew...
==> Installing gometalinter from alecthomas/tap
==> Downloading https://github.com/alecthomas/gometalinter/releases/download/v3.0.0/gometalinter-3.0.0-darwin-amd64.tar.gz
==> Downloading from https://github-production-release-asset-2e65be.s3.amazonaws.com/22629932/3d9cc000-2474-11e9-97b7-bf6c704eef1f?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F
######################################################################## 100.0%
🍺  /usr/local/Cellar/gometalinter/3.0.0: 28 files, 103MB, built in 2 minutes 41 seconds

でも実際は。

実際

Updating Homebrew...
==> Auto-updated Homebrew!
Updated 4 taps (homebrew/core, homebrew/cask, homebrew/bundle and homebrew/cask-fonts).
==> New Formulae
(省略)
==> Updated Formulae
(省略)

==> Tapping alecthomas/tap
Cloning into '/usr/local/Homebrew/Library/Taps/alecthomas/homebrew-tap'...
remote: Enumerating objects: 4, done.
remote: Counting objects: 100% (4/4), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 4 (delta 0), reused 0 (delta 0), pack-reused 0
Receiving objects: 100% (4/4), done.
Tapped 1 formula (26 files, 25.4KB).
Updating Homebrew...
==> Installing gometalinter from alecthomas/tap
==> Downloading https://github.com/alecthomas/gometalinter/releases/download/v3.0.0/gometalinter-3.0.0-darwin-amd64.tar.gz
==> Downloading from https://github-production-release-asset-2e65be.s3.amazonaws.com/22629932/3d9cc000-2474-11e9-97b7-bf6c704eef1f?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F
######################################################################## 100.0%
🍺  /usr/local/Cellar/gometalinter/3.0.0: 28 files, 103MB, built in 2 minutes 41 seconds
==> `brew cleanup` has not been run in 30 days, running now...
Removing: /usr/local/Cellar/awk/20121220... (5 files, 159.8KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bat--0.8.0.high_sierra.bottle.tar.gz... (2.2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/cmake--3.12.3.high_sierra.bottle.tar.gz... (11.9MB)
Removing: /usr/local/Cellar/docker-machine-driver-xhyve/0.3.3... (3 files, 10.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/docker-machine-driver-xhyve--0.3.3_1.high_sierra.bottle.tar.gz... (3.4MB)
Removing: /usr/local/Cellar/gdbm/1.15... (19 files, 569.8KB)
Removing: /usr/local/Cellar/gdbm/1.16... (19 files, 578.5KB)
Removing: /usr/local/Cellar/gdbm/1.17... (20 files, 581.4KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/gdbm--1.18.1.high_sierra.bottle.tar.gz... (192.4KB)
Removing: /usr/local/Cellar/glide/0.13.1... (6 files, 10.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/go--1.11.2.high_sierra.bottle.tar.gz... (140.5MB)
Removing: /usr/local/Cellar/hashpump/1.2.0_1... (10 files, 212.0KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/hugo--0.51.high_sierra.bottle.tar.gz... (18.2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/kubernetes-cli--1.12.2.high_sierra.bottle.tar.gz... (18.9MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/lynis--2.7.0.tar.gz... (270.5KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/mercurial--4.8.high_sierra.bottle.tar.gz... (2.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/sqlite--3.25.2.high_sierra.bottle.tar.gz... (1.8MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/tfenv--0.6.0.tar.gz... (9.2KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/icu4c-62.1.high_sierra.bottle.tar.gz... (25.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/node-10.9.0.high_sierra.bottle.tar.gz... (13MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bazaar-2.7.0_1.high_sierra.bottle.tar.gz... (3.8MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/grc-1.11.3.tar.gz... (44.1KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/xhyve-0.2.0.high_sierra.bottle.1.tar.gz... (10.9MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/tree-1.7.0.high_sierra.bottle.1.tar.gz... (48.3KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/rbenv-1.1.1.high_sierra.bottle.tar.gz... (18.6KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/htop-2.2.0.high_sierra.bottle.tar.gz... (82.4KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/pkg-config-0.29.2.high_sierra.bottle.tar.gz... (235.8KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bat-0.4.1.high_sierra.bottle.tar.gz... (2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bash-4.4.23.high_sierra.bottle.tar.gz... (2.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/hashpump-1.2.0_1.high_sierra.bottle.tar.gz... (65.4KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/tig-2.4.1.high_sierra.bottle.tar.gz... (266.9KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/ack-2.24.24-single-file... (138.3KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/ruby-build-20180618.tar.gz... (56.9KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/mysql-8.0.12.high_sierra.bottle.tar.gz... (59.4MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/mkcert-1.1.1.high_sierra.bottle.tar.gz... (1.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/libev-4.24.high_sierra.bottle.tar.gz... (140.8KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/ctop-0.7.1.high_sierra.bottle.tar.gz... (2.2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/openssl-1.0.2p.high_sierra.bottle.tar.gz... (3.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/openssl-1.0.2o_2.high_sierra.bottle.tar.gz... (3.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/autoconf-2.69.high_sierra.bottle.4.tar.gz... (871.2KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/kubernetes-cli-1.11.2.high_sierra.bottle.tar.gz... (13.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/docker-machine-driver-xhyve-0.3.3.high_sierra.bottle.1.tar.gz... (3.6MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/awk-20121220.high_sierra.bottle.tar.gz... (68.7KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bash-completion-1.3_3.high_sierra.bottle.tar.gz... (142.2KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/bat-0.5.0.high_sierra.bottle.tar.gz... (2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/linkage.db... (164KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/docker-machine-0.15.0.high_sierra.bottle.tar.gz... (7.4MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/git-2.18.0.high_sierra.bottle.tar.gz... (13.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/gdbm-1.17.high_sierra.bottle.tar.gz... (190.7KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/yarn-1.9.4.tar.gz... (915.4KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/p7zip-16.02_1.high_sierra.bottle.tar.gz... (2.0MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/boost-1.67.0_1.high_sierra.bottle.tar.gz... (87.1MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/readline-7.0.5.high_sierra.bottle.tar.gz... (494KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/direnv-2.17.0.high_sierra.bottle.tar.gz... (1.9MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/lynis-2.6.7.tar.gz... (268.5KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/mercurial-4.7.high_sierra.bottle.tar.gz... (2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/rename-1.600.high_sierra.bottle.tar.gz... (12.8KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/cmake-3.12.1.high_sierra.bottle.tar.gz... (12.0MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/gettext-0.19.8.1.high_sierra.bottle.tar.gz... (7.8MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/xz-5.2.4.high_sierra.bottle.tar.gz... (372.7KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/go-1.10.3.high_sierra.bottle.tar.gz... (102.6MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/sqlite-3.24.0.high_sierra.bottle.tar.gz... (1.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/dark-mode-2.0.1.high_sierra.bottle.tar.gz... (2.9MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/pv-1.6.6.high_sierra.bottle.tar.gz... (34.5KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/gibo-2.1.0.tar.gz... (6.7KB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/nmap-7.70.high_sierra.bottle.tar.gz... (7.1MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/glide-0.13.1.high_sierra.bottle.tar.gz... (3.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/mas-1.4.1.high_sierra.bottle.tar.gz... (3.0MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/peco-0.5.3.high_sierra.bottle.tar.gz... (1.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/lunar--2.1.1.dmg... (13.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/calibre--3.30.0.dmg... (76.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/insomnia--5.16.6.dmg... (58.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/the-unarchiver--4.0.0,120:1528909123.zip... (12.7MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/imagealpha--1.5.1.tar.bz2... (1.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/google-japanese-ime--latest.dmg... (67.8MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/visual-studio-code--1.24.1,24f62626b222e9a8313213fb64b10d741a326288.zip... (68.6MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/vitalsource-bookshelf--7.5.1.dmg... (35.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/spotify--latest.dmg... (96.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/imageoptim--1.8.0.tar.bz2... (2.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/onyx--3.4.5.dmg... (8.2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/alfred--3.6.1_910.dmg... (2.8MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/minikube--0.28.0... (40.6MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/teamsql--3.4.230.dmg... (82.0MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/atom--1.27.2.zip... (140MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/libreoffice--6.1.4.dmg... (237.6MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/google-chrome--67.0.3396.87.dmg... (66.3MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/font-fira-code--1.205.zip... (2MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/dashlane--latest... (48.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/dashlane--6.1903.0.16892.dmg... (44.1MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/appcleaner--3.4.zip... (2.5MB)
Removing: /Users/yusukekomatsu/Library/Caches/Homebrew/Cask/sequel-pro--1.1.2.dmg... (10.1MB)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/mkcert... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/go... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/hugo... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/gdbm... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/cmake... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/glide... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/awk... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/spotctl... (103B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/sqlite... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/yarn... (100B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/docker-machine-driver-xhyve... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/mercurial... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/tfenv... (101B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/bat... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/shpotify... (104B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/kubernetes-cli... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/node... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/openssl... (64B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/lynis... (101B)
Removing: /Users/yusukekomatsu/Library/Logs/Homebrew/hashpump... (64B)
Pruned 0 symbolic links and 2 directories from /usr/local

警告が出てたので、読んでみると

本文

`brew cleanup` has not been run in 30 days, running now...

超訳

J( '-`)し こらっ、もうこれいらないんでしょ！？ ゴミはちゃんと片付けなさい

お、おかんや！！おかんがおる！！

というわけで、brew cleanup しなくても30日たったら勝手にやってくれるようになりました。