You can interrupt a process, you can kill a process, you can make a process sleep, you can stop a process
But you CANNOT hide a process. What your friend might have done is done some trick to fool off you people.
Note that,
$ ps -ax is an incorrect syntax, and does not show complete process listing.
Just have a look at this small example that i have written:
Code:
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
int i;
for(i = 0; i < argc; i++)
memset(argv[i], 0, strlen(argv[i]));
for(;;);
}
what this does is destroys the argument table generated by executing the program. now if you go and view the file
/proc/pid/cmdline then you'll notice that this file is empty since we destroyed argv variable.
compile and execute this program by:
$ gcc -o phide phide.c
# ./phide
now if you give
$ ps aux then nothing would be shown.. However you can still view the program's listing by :
$ ps -u anurag -U anurag
replace anurag with the username who is executing the program. and you'll find the process phide listed.
Ask your friend to prove the he can hide processes for real or if he's playing some hiding trick.