bash local aliases / per-directory aliases in bash

..install.txt

// download .bash_local_aliases file and cd to the download directory

$ cp .bash_local_aliases ~/
$ if ! grep -qF 'source ~/.bash_local_aliases' ~/.bashrc; then echo -e "\nsource ~/.bash_local_aliases" >> ~/.bashrc; fi
$ source ~/.bash_local_aliases && cd .

// place a .aliases file anywhere, in the space-delimited "alias command" format shown in the .aliases example in this gist
// IMPORTANT: .aliases file should end with a single blank, empty line

$ cd .
$ myNode -e 'console.log(process.execArgv)'
$ nv

// place a different .aliases file in another directory
// then `cd` to it, and experience the magic of per-directory bash aliases

.aliases

myNode node --experimental-json-modules --no-warnings
nv node -v

.bash_local_aliases

function _brunner_runMethod() {
  if [ "$1" != "/" ]; then
    # traverse up directory tree, deepest directory wins if duplicate aliases found
    _brunner_runMethod "$(dirname "$1")" "$2"
  fi

  if [ -f "$1/.aliases" ]; then
    _brunner_parseAliases "$1/.aliases" "$2"
  fi
}

function _brunner_parseAliases() {
  # per-directory .brunner file must end with an empty line
  while read -r line; do
    aliasName=$(echo "$line" | cut -d' ' -f1)
    aliasContent=$(echo "$line" | cut -d' ' -f2-)
    "$2" "$aliasName" "$aliasContent"
  done < "$1"
}

function _brunner_unsetAlias() {
  unalias "$1" 2>/dev/null
}

function _brunner_setAlias() {
  alias "$1"="$2";
}

function cd() {
  _brunner_runMethod "$(pwd)" _brunner_unsetAlias
  command cd "$@" || return
  _brunner_runMethod "$(pwd)" _brunner_setAlias
}

# so it applies to the first directory when opening a new shell
_brunner_runMethod "$(pwd)" _brunner_setAlias