字符串处理

[leo@hadoop ~]$ cat string.sh
#!/bin/sh
a='weihongrao';
echo ${#a}

echo `expr index "$a" hong`
echo "another method:"
b=$(expr index "$a" hong)
echo $b

echo "substring"
a="you are my love"
b=${a:0:4}
echo $b
echo below will wrong do not know why so fay
d=`expr substr $a 1 5`
echo $d


echo --------
a="adfsdfsdcfsdfsdfcweihongrao"
echo $a
b=${a#a*c}
echo $b
b=${a##a*c}
echo $b
b=${a%c*o}
echo $b
b=${a%%c*o}
echo $b

echo repalce string
a='wei wei wei hong hong rao rao'
b=${a/wei/huang}
echo $b
b=${a//wei/huang}
echo $b
c=${a//wei/huang}
echo $c


一个简单的办法获取文件名和路径

[leo@hadoop ~]$ a=${PWD}/test.sh
[leo@hadoop ~]$ echo $a
/home/leo/test.sh
[leo@hadoop ~]$ echo ${a#*/}
home/leo/test.sh
[leo@hadoop ~]$ echo ${a##*/}
test.sh
[leo@hadoop ~]$ echo ${a%/*}
/home/leo
[leo@hadoop ~]$