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From: ron@well.sf.ca.us (Ronald Hayden)
Newsgroups: comp.unix.questions,comp.lang.c
Subject: Re: UNIX commands in C
Message-ID: <24527@well.sf.ca.us>
Date: 1 May 91 05:07:42 GMT
References: <1991Apr28.153127.24926@jack.sns.com>
Lines: 27

jtanner@jack.sns.com (Jason Tanner) writes:


>    I have been programming C for a while on IBM compats. using Turbo-C
>from Borland. Now I would like to move up to programing C in the UNIX
>enviroment. I know how to use all the regular C commands but I would like
>to know how to use UNIX commands from within a C program. For example
>to have the option to show who is online from within a program. I dont
>want this done with a shell escape I want it to be an potion like from a
>menu/list.
>   Thank you in advance.  Please Email or post all replies.
>-- 

There are actually several ways to do this (check out the book C
Programming In a UNIX Environment for a complete discussion), but for
a simple command such as "who", you can simply:


#include <stdio.h>

main ()
{
 printf("\nTesting the UNIX 'who' command --\n");
 system("who");
 printf("\nDone.\n");
 exit(1);
}