shell中的字符串索引一会从0开始，一会从1开始，见例子：
#!/bin/bash string="hello world" length=${#string} echo "string is ""$string""" echo "length is $length" index=`expr index "$string" 'o'` echo "index of 'o' is $index" substring=${string:$index} echo "substring begins from index $index is ""$substring""" echo "shit happens" echo exit 0
输出如下：
