#/bin/bash
str=12313;
le1=`expr "$str" : ".*"`;
le2=`expr length $str`;
le3=`echo $str | awk '{print length($0)}'`;
le4=`echo ${str} | wc -L`;
echo $le1 $le2 $le3 $le4
判断字符串为空的方法有三种:
if [ "$str" = "" ]
if [ x"$str" = x ]
if [ -z "$str" ]
注意:都要代双引号,否则有些命令会报错,养成好习惯吧!