[求助] 对 getopts 的疑问！

johnny_jiang

1. 
   
2. 
   
3. # filename: getopts-test
   
4. 
   
5. while getopts ":mnopq:rs" Option
   
6. do
   
7.         case $Option in
   
8.           m      ) echo "Scenario #1: option -m- [OPTIND=${OPTIND}]";;
   
9.           n|o   ) echo "Scenario #2: option -$Option-   [OPTIND=$OPTIND]";;
   
10.           p      ) echo "Scenario #3: option -p- [OPTIND=$OPTIND]";;
    
11.           q      ) echo "Scenario #4: option -q-\
    
12. with argument "$OPTARG"       [OPTIND=$OPTIND]";;
    
13.           #  Note that option 'q' must have an associated argument,
    
14.           #+ otherwise it falls through to the default.
    
15.           r|s    ) echo "Scenario #5: option -$Option-";;
    
16.           *      ) echo "Unimplemented option chosen.";;
    
17.         esac
    
18. done
    
19. 
    

复制代码

1. 
   
2. 
   
3. bash# ./getopts-test -mppnn
   
4. 
   
5. Scenario #1: option -m- [OPTIND=1]
   
6. Scenario #3: option -p- [OPTIND=1]
   
7. Scenario #3: option -p- [OPTIND=1]
   
8. Scenario #2: option -n- [OPTIND=1]
   
9. Scenario #2: option -n- [OPTIND=2]
   
10. 
    

复制代码

As a matter of fact, I am not sure how this script runs. The variable OPTIND seems not to be that reliable.

johnny_jiang

Up!Up!Up!

yongjian

abs mentioned that OPTIND is not reliable to tell where the option is coming from. It seems to treat "-mnop" style as a whole and strip down one char a time. If you "-m -n -o -p", OPTIND will be incremental.

johnny_jiang

Post by yongjian
abs mentioned that OPTIND is not reliable to tell where the option is coming from. It seems to treat "-mnop" style as a whole and strip down one char a time. If you "-m -n -o -p", OPTIND will be incremental.

Oh, yeah. I found it in abs. A little depressed.

Anyway, thanks for your help, yongjian.

johnny_jiang

Post by yongjian
abs mentioned that OPTIND is not reliable to tell where the option is coming from. It seems to treat "-mnop" style as a whole and strip down one char a time. If you "-m -n -o -p", OPTIND will be incremental.

Oh, yeah. I found it in abs. A little depressed.

Anyway, thanks for your help, yongjian.

johnny_jiang

Post by yongjian
abs mentioned that OPTIND is not reliable to tell where the option is coming from. It seems to treat "-mnop" style as a whole and strip down one char a time. If you "-m -n -o -p", OPTIND will be incremental.

Oh, yeah. I found it in abs. A little depressed.

Anyway, thanks for your help, yongjian.