function isDigit(s) { var patrn=/^[0-9]{1,20}$/; if (!patrn.exec(s)) return false return true } //校验登录名：只能输入5-20个以字母开头、可带数字、“_”、“.”的字串 function isRegisterUserName(s) { var patrn=/^[a-zA-Z]{1}([a-zA-Z0-9]|[._]){4,19}$/; if (!patrn.exec(s)) return fal
options: -s single-line mode -m multi-line mode -i ignoreCase -G global -R from right to left -E extended-regexp pattern ERE -e ="PAT-regexp" -C ="strToOperate" -F fixed-strings fgrep -c ="num" print only a count of matching first lines per file -n
