#!/usr/bin/env bash

perms=(___ __x _w_ _wx r__ r_x rw_ rwx)

perms() {
  local perm perm_str

  for perm do
    perm_str=$perm_str${perms[$perm]}
  done

  printf %s "$perm_str"
}

for owner in {0..7}; do
  for group in {0..7}; do
    for universe in {0..7}; do
      printf 'chmod_%s() {\n' "$(perms "$owner" "$group" "$universe")"
      printf '  chmod %d%d%d "$@"\n' "$owner" "$group" "$universe"
      printf '}\n'
      printf '\n'
    done
  done
done