help me(my homework) please!

donotexpert · 08-20-2005, 03:37 AM

a)List the number of unique users that has active processes.
b)List the number of active processes for each of the users in (a).
c)Execute “ps–ef> ps.out”command and enclose in the report. Determine the total number of CPU load in “ps.out”.
d)Determine total memory usage for each user.

you can helping me I don't know to begin this ploblem ?
I know it's easy for you

Simon Bridge · 08-20-2005, 04:12 AM

Ooooh... homework help aye?
Listen: you have to do your own homework.
However: I can help you understand your homework questions and put you on the right track OK? (And shame on anyone who just supplies the method...)

in terminal, "man ps", will tell you all about what ps does and is, and supplies example of how to use it. English language will be a problem for you here - but care will help you: this is one of the simpler man pages.

$ ps
will display a list of running processes to stdout (the terminal). For eg. On my system I get

Code:

[~]$ ps
  PID TTY          TIME CMD
 4179 pts/1    00:00:00 bash
 4827 pts/1    00:00:00 ps

You can get a record in a text file by typing
$ ps > foo.txt
... and you'll fine a file called "foo.txt" with the same stuff in it in whatever directory you were in when you typed the line. Of course, it is useful to choose a discriptive file name... like "ps.out" suggested by the teacher.

ps can be run with various options to alter the output.
for eg: $ps -f gives you the "full" description of the processes. Again, for me, this is:

Code:

 [~]$ ps -f
UID        PID  PPID  C STIME TTY          TIME CMD
simon     4179  5619  0 20:01 pts/1    00:00:00 bash
simon     4859  4179  0 21:11 pts/1    00:00:00 ps -f

See the difference?

the -e flag gives you "everything"... a list of all processes running on the machine. This can be rather long so I'll not give you an example.

$ps -e -f
is the same as
$ps -ef
and gives you a full list of all the processes.

This should be enough to start you off.
What you need in written in the man page for ps.
Good luck.

donotexpert · 08-20-2005, 04:30 AM

thank alot and I want to know how to creat for gcc program

exsample

#include <stdlib.h>
#include <stdio.h>
int main()
{
printf(“Running ps with system\n”);
system(“ps -u”);
printf(“Done.\n”);
exit(0);
}

it show
Running ps with system
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 2457 0.0 0.4 1740 404 tty1 Ss+ Aug16 0:00 /sbin/mingetty tt
root 2458 0.0 0.4 1952 408 tty2 Ss+ Aug16 0:00 /sbin/mingetty tt
root 2461 0.0 0.4 2572 408 tty3 Ss+ Aug16 0:00 /sbin/mingetty tt
root 2462 0.0 0.4 2372 408 tty4 Ss+ Aug16 0:00 /sbin/mingetty tt
root 2570 0.0 0.4 3012 408 tty5 Ss+ Aug16 0:00 /sbin/mingetty tt
root 2583 0.0 0.4 1564 408 tty6 Ss+ Aug16 0:00 /sbin/mingetty tt
root 3041 0.0 1.4 5368 1392 pts/1 Ss Aug16 0:00 -bash
root 3083 37.0 0.8 2580 772 pts/1 R+ 01:31 0:00 ps -u
Done

I want to use this program that show
only user

how to make this program ?

keefaz · 08-20-2005, 05:23 AM

Run your program as normal user

Simon Bridge · 08-20-2005, 06:26 AM

donotexpert: when you use linux, you should always be a normal user. Never run anything as root that you don't have to.

BTW: you realise this is easier to run with a script? Something like:

Code:

#!/bin/sh
echo -n "Running ps from the $0 script."
ps -u
echo "Done."

write this in a text file filename.sh, change the permissions so it is executable by you.
type ./filename.sh to execute it. To change user, you can add "su $1" and "exit" before and after the "ps -u" command. Then run the script with "./filename username". (See "man su" to see what it is about.) Of course, you'll need the users password.

You could also use sudo instead of su (it's tougher to set up but easier to use once it is.)

Or, of course, you could read the ps man page and it will tell you how to use ps -u to print the processes run by another user...

(Remember, I'm not actually going to do your homework for you...)