//vd1: vi du ve nhan ban tien trinh

#include<stdio.h>

void main()

{

int pid;

printf("day la tien trinh goc co pid=%d

, co cha la ppid=%d", getpid(),getppid());

pid=fork();//de nhan ban tien trinh

if ( pid!=0 )

printf("day la tien trinh cha co pid=%d", getpid());

else

printf("day la tien trinh con co pid=%d, ppid=%d", getpid(), getppid());

}//main

Lvfile

#include<stdio.h>

void main()

{

//thay doi chu so huu, nhom so huu file

int test1= chown("/home/ncnhungep/ltc/quyentruynhap.c",502,501);

if (test1==-1)

printf("doi chu so huu va nhom sh khong thanh cong !

");

else

printf("thay doi chu sh +nhom SH thanh cong !

");

//chu y neu chi muon thay doi uid hoac gid thi thong so ko muon thay doi de bang -1 vidu:

// chown("vd.c",500,-1);

//luu ly file muon thay doi chu sh thi phai dc co quyen thuc thi dung chmod truoc lenh nay neu bao ko thay doi thanh cong !

}

Mởi file

#include<stdio.h>

#include<fcntl.h>

void main()

{

int fd;//fd la mot so nguyen, la mo ta file tra ve 1 so nguyen khac -1 neu thanh cong va nguoc lai.

fd =open("wait.c",O_CREAT|O_RDWR);

if(fd!=-1)

printf("mo file ko thanh cong

");

else

{

//cac lenh doc ghi file

int rd=(fd,"wait.c",256);

if (rd!=-1)

printf("do thanh cong ");

else

printf("doc khong thanh cong ");

close(fd);

printf("da dong file thanh cong !");

}

}

tao mot tien trinh bo vo

#include<stdio.h>

void main()

{

int pid;

printf("tien trinh goc co pid=%d, ppid=%d

",getpid(),getppid());

pid=fork();//nhan ban tien trinh

if(pid!=0)

{

printf("toi la cha toi co pid la:%d

",getpid());

printf("tien trinh con cua toi co pid=%d

",pid);

}//if

else

{

sleep(10);

printf("day la tien trinh con co pid=%d, ppid=%d

", getpid(),getppid());

}//else

printf("tien trinh co pid=%d ket thuc

",getpid());

}//main

Prombie

#include<stdio.h>

void main()

{

int pid;

printf("toi la tien trinh goc co pid=%d, ppid=%d

",getpid(),getppid());

pid =fork();//nhan ban tien trinh

if( pid!=0 )

{

printf("tien trinh cha dc dua vao trang thai sleep trong vong lap vo han nen khong chap nhan ma ket thuc cua tien trinh con da gui? nen tien trinh con luc nay tro thanh tien trinh zombie

");

while(1)

sleep(10);

printf("lenh nay khong bao gio dc thuc hien");

}//if

else

{

exit(42);

printf("toi la tien zombie co pid=%d, ppid=%d

",getpid(),getppid());

printf("toi ko the kt vi cha ko nhan ma ket thuc (*^<>^)

");

}

}//main

Quyentruynhap

#include<stdio.h>

void main()

{

            //kiem tra khi chua thay doi quyen truy nhap:ls -l wait.c

            int kt=chmod("wait.c",0777);

            if ( kt==-1 )

            printf("thay doi quyen truy nhap khong thanh cong

");

            else

            printf ("thanh cong !

");

//kiem tra sau khi thay doi quyen thanh cong:ls -l wait.c

}

//vd1: vi du ve nhan ban tien trinh

#include<stdio.h>

void main()

{

int pid;

printf("day la tien trinh goc co pid=%d, co cha la ppid=%d

", getpid(),getppid());

pid=fork();//de nhan ban tien trinh

if ( pid!=0 )

printf("day la tien trinh cha co pid=%d

", getpid());

else

printf("day la tien trinh con co pid=%d, ppid=%d

", getpid(), getppid());

}//main

Wait

#include<stdio.h>

void main()

{

int pid, status;

pid=fork();

if(pid!=0)

{

printf("tien trinh cha co pid=%d

",getpid());

int child=wait(&status);

printf("tien trinh con ket thuc voi pid=%d,ma ket thuc =%d

",child,status>>8);

}//if

else

{

printf("day la tien trinh con

");

exit(42);

}//else

}//main