On Mon, Apr 19, 2010 at 2:49 PM, subhojit ojha <subhojit.o...@gmail.com>wrote:
> Hi all,
> I know what is getopts and what is the syntax, how to use it...But I
> have never came across any shell program where I have been used getopts, is
> here any one who has implemented getopts in their shell program.....
> If any body have used, plz share ur experience...Just want to know in which
> condition we are using getopts.
>
>
Hi,
I don't know how to explain the below usage in shell script. But I will
explain the usage in C. I have created this very simple program to show you
the usage of getopt(). Let us assume that the below program is your
application(calculation.c). This program will call the function sum(),
sub(), mul() and divi() depending upon the option (-S,-s,-m,-d). This is
the one way parsing command line argument within your application. compile
and execute the program. You will feel the usage .
//This very basis example will show you the getopt usage
//calculation.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int sum(int , int);
int sub(int , int);
int mul(int , int);
int divi(int , int);
void usage();
int main(int argc , char *argv[])
{
int c;
int input1;
/* process arguments */
while (-1 != (c = getopt(argc, argv,"S:" "s:" "m:" "d:" "h")))
{
switch (c)
{
case 'S':
input1=atoi(optarg);
printf("Sum : %d\n",sum(input1,2));
break;
case 's':
input1=atoi(optarg);
printf("Sub : %d\n",sub(input1,2));
break;
case 'm':
input1=atoi(optarg);
printf("Mul : %d\n",mul(input1,2));
break;
case 'd':
input1=atoi(optarg);
printf("Div : %d\n",divi(input1,2));
break;
case 'h':
printf("usage goes here\n");
usage();
break;
default:
exit(0);
}
}
return 0;
}
//addition
int sum(int x , int y)
{
return (x+y);
}
//subtraction
int sub(int x, int y)
{
return (x-y);
}
//Multiplication
int mul(int x, int y)
{
return (x*y);
}
//devision
int divi(int x, int y)
{
return (x/y);
}
void usage()
{
printf("./caculation -S <num1>\twill add: num1+2\n");
printf("./caculation -s <num2>\twill sub: num2-2\n");
printf("./caculation -m <num3>\twill mul: num3*2\n");
printf("./caculation -d <num4>\t will div: num4\2\n");
printf("./caculation -h \twill display this help message\n");
}
Compile :
$ gcc -Wall calculation.c -o claculation
Execute the program with deffent option:
$./claculation -S 10
$./claculation -S 10 -s 20
$./claculation -S 10 -s 20 -m 5
$./claculation -S 10 -s 20 -m 5 -d 30
If you have any questions, please don't hesitate to contact me.
Now take the below link
http://www.mkssoftware.com/docs/man1/getopt.1.asp
I hope this may help you.
Thanks & Rg
Mohan L
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