Get normal or system user accounts from `getent passwd` with values from login.defs

get-users

#!/bin/bash

# get-users
# Get normal or system user accounts from `getent passwd` with values from login.defs
# Andres Hernandez - tonejito
#
# This script is released under the GPL license version 3
#
# Usage:
#    get-users [[--]users | [--]system]

AWK=/usr/bin/awk
GREP=/bin/grep
GETENT=/usr/bin/getent

LOGIN_DEFS=/etc/login.defs
UID_MIN="`$GREP ^UID_MIN $LOGIN_DEFS | $AWK '{print $2}'`"
UID_MAX="`$GREP ^UID_MAX $LOGIN_DEFS | $AWK '{print $2}'`"

AWK_FILTER_USERS='{if($3>=UID_MIN&&$3<UID_MAX){print}}'
AWK_FILTER_SYSTEM='{if($3<UID_MIN||$3>=UID_MAX){print}}'

case "${1}"
in
  --system|system)
    FILTER=$AWK_FILTER_SYSTEM
    ;;
  --users|users|*)
    FILTER=$AWK_FILTER_USERS
    ;;
esac

$GETENT passwd | \
$AWK -F : \
  -vUID_MIN="${UID_MIN}" \
  -vUID_MAX="${UID_MAX}" \
  $FILTER \
;