Fix hardcoded Homebrew prefix

The Homebrew prefix was hardcoded to /usr/local in ~/.bashrc and
~/.bash_profile. However, on newer Apple chip computers, the default
prefix is /opt/homebrew (see [1]). These hardcoded prefixes have been
replaced by $(brew --prefix) to determine the prefix dynamically.

Also, unnecessary PATH and variable settings have been outcommented in
~/.bash_profile.

[1] https://docs.brew.sh/FAQ#why-should-i-install-homebrew-in-the-default-location

Author: weibeld

.bash_profile

@@ -21,44 +21,50 @@ if [[ "$OSTYPE" =~ darwin ]]; then
   export HISTSIZE=5000
   export HISTFILESIZE=5000
 
+  # Homebrew
+  # Correct prefix depends on chip architecture (Intel or Apple).
+  # See https://docs.brew.sh/FAQ#why-should-i-install-homebrew-in-the-default-location
+  eval $(/opt/homebrew/bin/brew shellenv)
+  #eval $(/usr/local/bin/brew shellenv)
+  export HOMEBREW_NO_AUTO_UPDATE=1
+
   # Java
   #export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-11.0.3.jdk/Contents/Home
-  export JAVA_HOME=/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home
-  export JUNIT_HOME=$JAVA_HOME/lib
-  export GROOVY_HOME=/usr/local/opt/groovy/libexec
+  #export JAVA_HOME=/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home
+  #export JUNIT_HOME=$JAVA_HOME/lib
+  #export GROOVY_HOME=/usr/local/opt/groovy/libexec
 
   # Misc
   export d=~/Desktop
-  export tex_home=/usr/local/texlive
+  #export tex_home=/usr/local/texlive
   export fonts_user=~/Library/Fonts
   export fonts_local=/Library/Fonts
   export fonts_system=/System/Library/Fonts
-  export PYTHONSTARTUP=~/.python
-  export GOPATH=$HOME/go
-  export HOMEBREW_NO_AUTO_UPDATE=1
-  alias chrome="/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome"
+  #export PYTHONSTARTUP=~/.python
+  #export GOPATH=$HOME/go
+  #alias chrome="/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome"
 
   # PATH
-  path_append "$HOME/bin"
-  path_append "/usr/local/sbin"
-  path_append "$HOME/.krew/bin"
-  path_append "$HOME/.kubectl-plugins"
-  path_append "$HOME/google-cloud-sdk/bin"
-  path_append "$HOME/platform-tools"
-  path_append "$(go env GOPATH)/bin"
-  path_prepend /usr/local/opt/ruby/bin
-  path_prepend /usr/local/lib/ruby/gems/2.6.0/bin
+  #path_append "$HOME/bin"
+  #path_append "/usr/local/sbin"
+  #path_append "$HOME/.krew/bin"
+  #path_append "$HOME/.kubectl-plugins"
+  #path_append "$HOME/google-cloud-sdk/bin"
+  #path_append "$HOME/platform-tools"
+  #path_append "$(go env GOPATH)/bin"
+  #path_prepend /usr/local/opt/ruby/bin
+  #path_prepend /usr/local/lib/ruby/gems/2.6.0/bin
   # GNU Make
-  path_prepend /usr/local/opt/make/libexec/gnubin
+  #path_prepend /usr/local/opt/make/libexec/gnubin
   # Homebrew version of curl
-  path_prepend /usr/local/opt/curl/bin
+  #path_prepend /usr/local/opt/curl/bin
   # sketchtool
-  path_append /Applications/Sketch.app/Contents/MacOS
+  #path_append /Applications/Sketch.app/Contents/MacOS
   # Added by serverless binary installer
-  export PATH="$HOME/.serverless/bin:$PATH"
+  #export PATH="$HOME/.serverless/bin:$PATH"
 
   # Command completion
-  complete -C /usr/local/bin/packer packer
+  #complete -C /usr/local/bin/packer packer
 
 fi
 

.bashrc

@@ -69,6 +69,14 @@ ensure() {
   which -s "$1" || { echo "Error: '$1' not installed."; return 1; } 
 }
 
+# Test whether a Homebrew formula or cask, respectively, is installed.
+is-homebrew-formula-installed() {
+  brew ls --versions "$1" >/dev/null
+}
+is-homebrew-cask-installed() {
+  brew ls --cask --versions "$1" >/dev/null
+}
+
 # Capitalise the first letter of a string
 capitalize () {
   echo $(echo "${1:0:1}" | tr '[:lower:]' '[:upper:]')"${1:1}"
@@ -311,9 +319,9 @@ __dump_history() {
 #------------------------------------------------------------------------------#
 
 if is-mac ; then
-  source /usr/local/etc/profile.d/bash_completion.sh
+  source $(brew --prefix)/etc/profile.d/bash_completion.sh
   # Source completion scripts of Homebrew formulas
-  for f in /usr/local/etc/bash_completion.d/*; do
+  for f in $(brew --prefix)/etc/bash_completion.d/*; do
     source "$f"
   done
 fi
@@ -1123,7 +1131,7 @@ sm() {
   smp && smd "$1"
 }
 
-complete -C /usr/local/bin/aws_completer aws
+complete -C $(brew --prefix)/bin/aws_completer aws
 
 #------------------------------------------------------------------------------#
 # Azure
@@ -1656,7 +1664,7 @@ prometheus-clean() {
 #------------------------------------------------------------------------------#
 
 # Terraform autocompletion (installed with terraform --install-autocomplete)
-complete -C /usr/local/bin/terraform terraform
+complete -C $(brew --prefix)/bin/terraform terraform
 
 alias tf=terraform
 #complete -F _complete_alias t
@@ -1671,8 +1679,10 @@ alias tfdd='terraform destroy --auto-approve'
 #------------------------------------------------------------------------------#
 if is-mac; then
 
-  # Use Vim installed by Homebrew
-  alias vim=/usr/local/bin/vim
+  # Use Homebrew Vim by default
+  if is-homebrew-formula-installed vim; then
+    alias vim=$(brew --prefix)/bin/vim
+  fi
 
   # Recursively delete all .DS_Store files in the current directory
   alias rmds='find . -type f \( -name .DS_Store -or -name ._.DS_Store \) -delete'