brewでJSONをインストールする際に表示されるエラーについて

###前提・実現したいこと
MacOSでターミナルに以下のように打ち込んで、JSONをインストールしようとしています。

$brew install jq

###発生している問題・エラーメッセージ
以下のようにエラーが7つ表示されたのですが、どのように対処すればいいかわからず、困っています。アドバイスをいただけましたら幸いです。

Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
aws-sdk-cpp                              pass
blackbox                                 passpie
bowtie2                                  percona-toolkit
check_postgres                           pex
coffeescript                             pg_top
duplicity                                pgpool-ii
ephemeralpg                              pius
fn                                       psqlodbc
geeqie                                   rbenv-aliases
git-secret                               rbenv-binstubs
gnumeric                                 rbenv-bundle-exec
gopass                                   rbenv-bundler
heroku                                   rbenv-bundler-ruby-version
hydra                                    rbenv-chefdk
innotop                                  rbenv-communal-gems
karn                                     rbenv-ctags
kitchen-sync                             rbenv-default-gems
libpqxx                                  rbenv-gemset
libpqxx@3                                rbenv-use
libzdb                                   rbenv-vars
mysql++                                  rbenv-whatis
mysql-connector-c++                      sysbench
mytop                                    weboob
osm2pgrouting                            x3270
osm2pgsql                                youtube-dl
pandoc                                   zabbix
pandoc-citeproc                          zero-install

Error: Could not link:
/usr/local/etc/bash_completion.d/brew

Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/zsh/site-functions/_brew

Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/man/man1/brew.1

Please delete these paths and run `brew update`.
Error: Could not link:
/usr/local/share/doc/homebrew

Please delete these paths and run `brew update`.
Error: No available formula with the name "iq" 
==> Searching for a previously deleted formula...
Warning: homebrew/core is shallow clone. To get complete history run:
  git -C "$(brew --repo homebrew/core)" fetch --unshallow

Error: No previously deleted formula found.
==> Searching for similarly named formulae...
==> Searching local taps...
These similarly named formulae were found:
asciiquarium    liquibase       liquid-dsp      liquidprompt    liquigraph
To install one of them, run (for example):
  brew install asciiquarium
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.

###補足情報(言語/FW/ツール等のバージョンなど)
ターミナルバージョン2.8
Mac OS high Sierra