something about linux shell 2

something about linux shell

rindex.sh代码：

#!/bin/bash

strToCheck=$1;
charToSearch=$2;

let pos=`echo "$strToCheck" | awk -F ''$charToSearch'' '{printf "%d", length($0)-length($NF)}'`

echo "char $charToSearch lastpos is: $pos"

使用示例：

[zeal]$ sh rindex.sh .
char . lastpos is: 10

则提供了一种比较自力更生的方式：自己用c写了个小程序来实现rindex的功能，gcc rindex.c -o rindex 之后shell就拥有可以调用的rindex了 :)

rindex.c代码：

#include 
int main(int argc, char *argv[]){
    char* wholeWord;
    char subChar;
    char* subWord;

    int ret;

    if(argc!=3){
        printf("Use:rindex word char ");
        exit(0);
    }
    wholeWord=argv[1];
    subChar=*argv[2];
    subWord=rindex(wholeWord,subChar);

    if(0 == subWord)
        ret = 0;
    else
        ret = (subWord-wholeWord+1);
    printf("%d ",ret);
}