OS Exec families C Program

Operating Systems Lab Manual / OS Exec families C Program

Program Name

Write a C Program for OS Exec families

Theory

Exec function family functions(execl, execlp, execle, execv and execvp) are used to execute a file.
The exec family of functions replaces the current running process with a new process.

int execl(const char *path, const char *arg, …, NULL);
int execlp(const char *file, const char *arg, …, NULL );
int execv(const char *path, char *const argv[]);
int execvp(const char *file, char *const argv[]);
int execle(const char *path, const char *arg, …, NULL, char * const envp[] );
int execve(const char *file, char *const argv[], char *const envp[]);

Program Code

#include<unistd.h> 
#include<sys/types.h> 
#include<stdio.h> 
#include<stdlib.h> 
int main()
{
char *a[10]; char n;
printf("\nSelect any Option\n);
printf("1.EXECL\t2.EXECLP\t3.EXECV\t4.EXECP\t5.EXIT\n");
scanf("%c",&n); 
switch(n)
{
case '1':execl("/bin/ls","ls",NULL); break;
case '2':execlp("ls","ls",NULL); break;
case '3':a[0]="ls";a[1]="-a"; 
a[2]=NULL;execv("/bin/ls",a); break;
case '4':a[0]="ls";a[1]="-a"; 
a[2]=NULL;execvp("ls",a); break;
case '5':exit(0);
default :printf("\nInvalid Choice");
}
return 0;
}

Input:

Output:
Stat Demo
USER ID is 0
GROUP ID IS 0
no of links 0
Time of last file access Wed Mar  4 05:51:52 1970
Time of last file modification Sun Apr  7 02:36:01 1974
Time of last file status change Wed Nov  6 00:36:28 1935

Block size 134513381
no of blocks 5365748
File size -1077859208
Inode no:0Id of device containing a dir entry for this file is 0
Id of device for char special or blk special file is 134513552

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