execlp command - Dev Shed

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June 29th, 2005, 05:57 PM

arun0000

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execlp command

Hi guys,

I am trying to use the execlp command in my C program to run the PS command and send the output into a file specified in the Argument. Following is the command that I am trying to use without any luck.
any help would be greatly appreciated.
Thanks, Arun

PHP Code:


		
			
#include <stdio.h>

main()

{

char Argument[10]

printf ("Enter Argument\n");

gets(Argument);



execlp("/bin/ps","ps > "%s",Argument",NULL);

}

June 30th, 2005, 10:27 AM

stdunbar

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I don't think all of your code is here. What is this line supposed to be?

Code:

execlp("/bin/ps","ps > "%s",Argument",NULL);

execlp() does not take printf() like arguments. Also, your double quotes are all over the place. Lastly, gets() is one of the most dangerous method calls ever created in the standard C library. If this is just a school project, ok. If this is meant to ever be used by someone besides you then it needs to be removed.

June 30th, 2005, 02:20 PM

arun0000

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Quote:

Originally Posted by stdunbar

I don't think all of your code is here. What is this line supposed to be?

Code:

execlp("/bin/ps","ps > "%s",Argument",NULL);

You are right, this is for a school project. I am trying to execute the UNIX's PS command in my C program. If I use the following command in my C program the PS command gets executed and the output of the PS command is written on the screen.
execlp("/bin/ps","ps",NULL);

But I need to change this command so the output of the PS command goes into a file, which is specified in the Argument as shown in the earliear code. I am not sure where to instert the Argument(file name) in this command.

Thanks

July 1st, 2005, 11:43 AM

stdunbar

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Take a look at the sprintf() man page. You'll want something on the order of:

Code:

char command[128];
sprintf( command, "ps > %s", argument );

execlp("/bin/sh", command, NULL);

You want to run the shell instead of ps as you want the redirect - that is a shell concept.

As a warning this is totally untested...

July 12th, 2005, 08:13 AM

guggach

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why not

Quote:

Originally Posted by arun0000

PHP Code:


		
			
#include <stdio.h>

/* since early '90 , is main a int, declared as

int main(int argc,char **argv)

and returns|exits an int :(

*/

main()

{

char Argument[10]

printf ("Enter Argument\n");

gets(Argument); 

/*VERY. VERY, VERY dangerous !!!!!!

the chance of a core dump is 99,99%

prefer something like

fgets(Argument,sizeof(Argument),stdin);

*/

execlp("/bin/ps","ps > "%s",Argument",NULL); /* that's no C */

/* re-read man pages of execlp */

/*try

#define BUFF 512

FILE *ps;

char buff[BUFF];

ps = popen("/bin/ps mybe-whith-options","r");

while(fgets(buff,sizeof(bufff),ps)) printf("%s",buff);

pclose(ps);

*/



}

at least: think about color-blind peoble, don't play with colors!!

__________________
working on Solaris[5-9], preferred languages french and C.

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