Custom version of the Bash 'type' command, navigating symlinks and aliases.

custom-type.bash

# All my gist code is licensed under the terms of the MIT license.

# Video demo: https://www.youtube.com/shorts/mYfEIZFlIwo

# Put this in your .bashrc or something like that

# pretty_print_directory
# - replace $HOME with ~
# - make everything before the last '/' green, and everything after white and
#   bold
# - takes a single argument or reads from stdin
function pretty_print_directory () {
  green='\x1b[32m'
  bold='\x1b[1m'
  reset='\x1b[0m'

  input=""
  if [[ "$#" == 0 ]]; then
    input="$(cat)"
  else
    input="$1"
  fi

  echo "$input" | \
  sed -E 's:'"$HOME"':~: ; s:$HOME:~: ; s:(.*/)([^/]+):'"${green}"'\1'"${reset}${bold}"'\2'"${reset}"':'
}

# custom type
# - Adds the -a flag (show all matches, not just the first)
# - Pretty print paths
# - Show symlink targets.
# - If any line is an alias, highlight the first word, and include a nested
#   type call for that word.
function type () {
  local gray='\e[38;5;8m'
  local blue='\e[34m'
  local bold='\e[1m'
  local reset='\e[0m'

  output="$(command type -a "$@")"

  # if there is no output, return
  if [[ -z "$output" ]]; then
    return 1
  fi

  local regex_path='^[[:graph:]]+ is [[:graph:]]+$' # case "WORD is /some/path"
  local regex_alias='^[[:graph:]]+ is aliased to'   # case "WORD is aliased to"
  local regex_is='^[[:graph:]]+ is '                # case "WORD is ..."
  
  # For every output line
  while IFS= read -r line; do
    # If line has the form "WORD is /some/path", pretty print the path and add
    # symlink target, if any.
    if [[ "$line" =~ $regex_path ]]; then
      local word="${line%% is*}"
      local path="${line#* is }"
      local pretty_path="$(pretty_print_directory "$path")"
      local output_line="${bold}${word}${reset} is ${pretty_path}"

      # symlink stuff
      local symlink_path="$(realpath "$path")"
      if [[ "$symlink_path" != "$path" ]]; then
        local pretty_symlink_path="$(pretty_print_directory "$symlink_path")"
        output_line="${output_line} ${gray}->${reset} ${pretty_symlink_path}"
      fi

      printf '%b\n' "$output_line"

    # If line has the form "WORD is aliased to `ALIAS ...", highlight alias
    elif [[ "$line" =~ $regex_alias ]]; then
      # Note that forms can be either:
      # - "WORD is aliased to `ALIAS ...'" or 
      # - "WORD is aliased to `ALIAS'"
      local word="${line%% is*}"
      local rest="${line#* is aliased to \`}"
      local alias="${rest%%[ \']*}"
      local rest="${rest#*${alias}}"

      local is_alias_different_command=false
      if [[ "$word" != "$alias" ]]; then
        is_alias_different_command=true
      fi

      # if the alias is different than the word, highligh as blue 
      local alias_highlight=${bold}
      if [[ "$is_alias_different_command" = true ]]; then
        alias_highlight=${bold}${blue}
      fi

      printf '%b\n' "${bold}${word}${reset} is aliased to \`${alias_highlight}${alias}${reset}${rest}"

      # if the alias is different, recursively call 'type' on it. Indent two spaces.
      if [[ "$is_alias_different_command" = true ]]; then
        local alias_output="$(type "$alias" | sed 's/^/  /')"
        printf '%b\n' "$alias_output"
      fi

    # If a line has the form "WORD is ...", highlight word.
    # This is just the catch-all case.
    elif [[ "$line" =~ $regex_is ]]; then
      local word="${line%% is*}"
      local rest="${line#* is }"
      printf '%b\n' "${bold}${word}${reset} is ${rest}"
    else
      printf '%s\n' "$line"
    fi
  done <<< "$output"
}