#!/bin/bashecho "input username and create user.(for example:firstuser user1 lastuser user5)"read -p "please input firstuser:  " FIRSTUSERread -p  "please input lastuser:  " LASTUSERFIRST=${FIRSTUSER##*[[:alpha:]]}LAST=${LASTUSER##*[[:alpha:]]}NAME=${FIRSTUSER%%[0-9]*}for i in `seq $FIRST $LAST`do    if  grep -q "$NAME$i"  /etc/passwd        then        continue    fi        useradd $NAME$idone