Quicker than typing cd ..

back.sh

#!/usr/bin/env bash

#----------
# back
#   Goes back to parent directory quicker.
#   
#   NUMBER - goes back to x levels by repeatedly calling `cd ..`.
#   SUBPATH - a segment of a full path to go back.
#
#   *KNOWN LIMITS*
#   - If the segment is a number, say 1234, use `back '/1234'`.
#   - If there are more than one occurences of the segment in the full path,
#   the first one will be used.
back() {
  local target="${1:-1}"
  local full_path="$(pwd)"

  # If the argument is a number, treat it as how many level or parents
  # to go back to.
  if [[ "$target" =~ ^[[:digit:]].*$ ]]
  then
    for x in {1..${target}}
    do
      cd ..
    done
    return 0
  else
    # If the argument is not a number, test if it is a segment in the path
    # of the current directory.
    # If it is, then calculate the path to the argument and then
    # simply cd to it.
    if [[ "${full_path}" == *"${target}"* ]]
    then
      # Implementation note:
      # Suppose the path is this/is/a/long/directory/path and the argument is `long`.
      # First we need to find the path starting after the argument `directory/path` by
      # using Bash Sub-string removal `${full_path##*target}`.
      # Then we substract that path to the full path to have the path to the argument.
      local trailing="${full_path##*${target}}"
      local target_path="${full_path%${trailing}*}"
      cd "${target_path}"
      # cd "${full_path%${target}*}/${target}"
      return 0
    else
      echo "error - cannot back to ${target} as it does not exist"
    fi
    return 1
  fi
}

back "$@"