Create new environment variable & print assignment statement to your shell's '.rc' file

new_env_var.sh

# -----------------------------------------
#  Create new environment variable & print assignment statement to your shell's '.rc' file
#
#  @1 = variable new
#  @2 = variable definition
#  @requires: '~/.zshrc' or '~/.bashrc'
# -----------------------------------------
function new_env_var {
  local detected_shell="$(ps -o comm= -p $$)"
  local rcfile=$(echo "${HOME}/.${detected_shell//-/}rc")
  if [[ -f $rcfile ]]; then
    local var_name; local var_val
    if [ -z "$1" ]; then
      echo "variable name (e.g. 'NEW_VAR' for '\$NEW_VAR'):"; read var_name
    else
      var_name=$1
    fi
    if [ -z "$2" ]; then
      echo "variable definition:"; read var_val
    else
      local s2 var_val="${@//${var_name}/}"
      until s2="${var_val#[   ]}"; [ "$s2" = "$var_val" ]; do var_val="$s2"; done
    fi
    echo "export $var_name=\"$var_val\"" >> $rcfile; export $var_name="$var_val"
  else
    echo "No $detected_shell runcom file found. Please make sure $rcfile exists."
  fi
}