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210 changes: 191 additions & 19 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,26 @@ Test the C Program for the desired output.
# PROGRAM:

## C Program to print process ID and parent Process ID using Linux API system calls
```
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main(void)
{ //variable to store calling function's process id
pid_t process_id;
//variable to store parent function's process id
pid_t p_process_id;
//getpid() - will return process id of calling function
process_id = getpid();
//getppid() - will return process id of parent function
p_process_id = getppid();
//printing the process ids

//printing the process ids
printf("The process id: %d\n",process_id);
printf("The process id of parent function: %d\n",p_process_id);
return 0; }
```



Expand All @@ -40,7 +59,13 @@ Test the C Program for the desired output.



##OUTPUT
##OUTPUT:
```
localhost:~# gcc -o output.c pidcheck.c
localhost:~# ./output.c
The process id: 96
The process id of parent function: 61
```



Expand All @@ -56,29 +81,99 @@ Test the C Program for the desired output.


## C Program to create new process using Linux API system calls fork() and exit()
```
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

int main() {
int pid;
pid = fork();
if (pid == 0) {
printf("I am child, my pid is %d\n", getpid());
printf("My parent pid is: %d\n", getppid());
exit(0);
} else {
printf("I am parent, my pid is %d\n", getpid());
sleep(100);
exit(0);
}
}
```
##OUTPUT:
```
localhost:~# gcc -o output.c pidcheck.c
localhost:~# ./output.c
I am parent, my pid is 96
I am child, my pid is 97
My parent pid is: 96
```

## C Program to execute Linux system commands using Linux API system calls exec() family
```
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <unistd.h>

int main() {
int status;
pid_t pid;

printf("Running ps with execlp\n");
pid = fork();

if (pid == 0) {
// This is the child process
execlp("ps", "ps", "ax", NULL);
// If execlp fails, print an error message
perror("execlp");
exit(EXIT_FAILURE);
} else if (pid > 0) {
// This is the parent process
wait(&status);
if (WIFEXITED(status)) {
printf("Child exited with status of %d\n", WEXITSTATUS(status));
} else {
puts("Child did not exit successfully");
}
} else {
// fork() failed
perror("fork");
exit(EXIT_FAILURE);
}

printf("Done.\n");

printf("Running ps with execl. Now with path specified\n");
pid = fork();

if (pid == 0) {
// This is the child process
execl("/bin/ps", "ps", "ax", NULL);
// If execl fails, print an error message
perror("execl");
exit(EXIT_FAILURE);
} else if (pid > 0) {
// This is the parent process
wait(&status);
if (WIFEXITED(status)) {
printf("Child exited with status of %d\n", WEXITSTATUS(status));
} else {
puts("Child did not exit successfully");
}
} else {
// fork() failed
perror("fork");
exit(EXIT_FAILURE);
}

printf("Done.\n");









##OUTPUT








## C Program to execute Linux system commands using Linux API system calls exec() family
return 0;
}
```



Expand Down Expand Up @@ -106,6 +201,83 @@ Test the C Program for the desired output.


##OUTPUT
```
localhost:~# gcc -o output.c pidcheck.c
localhost:~# ./output.c
Running ps with execlp
PID USER TIME COMMAND
1 root 0:01 {init} /bin/sh /sbin/init
2 root 0:00 [kthreadd]
3 root 0:00 [kworker/0:0]
4 root 0:00 [kworker/0:0H]
5 root 0:00 [kworker/u2:0]
6 root 0:00 [mm_percpu_wq]
7 root 0:00 [ksoftirqd/0]
8 root 0:00 [kdevtmpfs]
9 root 0:00 [oom_reaper]
10 root 0:00 [writeback]
11 root 0:00 [kcompactd0]
12 root 0:00 [crypto]
13 root 0:00 [bioset]
14 root 0:00 [kblockd]
14 root 0:00 [kblockd]
15 root 0:00 [kworker/0:1]
16 root 0:00 [kswapd0]
17 root 0:00 [bioset]
34 root 0:00 [khvcd]
35 root 0:00 [bioset]
36 root 0:00 [bioset]
37 root 0:00 [bioset]
38 root 0:00 [bioset]
39 root 0:00 [bioset]
40 root 0:00 [bioset]
41 root 0:00 [bioset]
42 root 0:00 [bioset]
55 root 0:00 settime -d /
56 root 0:00 dhcpcd -q
61 root 0:00 sh -l
62 root 0:00 [kworker/u2:1]
103 root 0:00 ./output.c
104 root 0:00 ps ax
Child exited with status of 0
Done.
Running ps with execl. Now with path specified
PID USER TIME COMMAND
1 root 0:01 {init} /bin/sh /sbin/init
2 root 0:00 [kthreadd]
3 root 0:00 [kworker/0:0]
4 root 0:00 [kworker/0:0H]
5 root 0:00 [kworker/u2:0]
6 root 0:00 [mm_percpu_wq]
7 root 0:00 [ksoftirqd/0]
8 root 0:00 [kdevtmpfs]
9 root 0:00 [oom_reaper]
10 root 0:00 [writeback]
11 root 0:00 [kcompactd0]
12 root 0:00 [crypto]
13 root 0:00 [bioset]
14 root 0:00 [kblockd]
15 root 0:00 [kworker/0:1]
16 root 0:00 [kswapd0]
17 root 0:00 [bioset]
34 root 0:00 [khvcd]
35 root 0:00 [bioset]
36 root 0:00 [bioset]
37 root 0:00 [bioset]
38 root 0:00 [bioset]
39 root 0:00 [bioset]
40 root 0:00 [bioset]
41 root 0:00 [bioset]
42 root 0:00 [bioset]
55 root 0:00 settime -d /
56 root 0:00 dhcpcd -q
61 root 0:00 sh -l
62 root 0:00 [kworker/u2:1]
103 root 0:00 ./output.c
105 root 0:00 ps ax
Child exited with status of 0
Done.
```



Expand Down