Linux – Hide arguments of commands in ps

Here you go:

$ ps  xao pid,ppid,pgid,sid | head
  PID  PPID  PGID   SID
    1     0     1     1
    2     0     0     0
    3     2     0     0
    6     2     0     0
    7     2     0     0
   21     2     0     0
   22     2     0     0
   23     2     0     0
   24     2     0     0

If you want to see the process' name as well, use this:

$ ps  xao pid,ppid,pgid,sid,comm | head
  PID  PPID  PGID   SID COMMAND
    1     0     1     1 init
    2     0     0     0 kthreadd
    3     2     0     0 ksoftirqd/0
    6     2     0     0 migration/0
    7     2     0     0 watchdog/0
   21     2     0     0 cpuset
   22     2     0     0 khelper
   23     2     0     0 kdevtmpfs
   24     2     0     0 netns

ps does not hide the password. Applications like mysql overwrite arguments list that they got. Please note, that there is a small time frame (possible extendible by high system load), where the arguments are visible to other applications until they are overwritten. Hiding the process to other users could help. In general it is much better to pass passwords via files than per command line.

In this article it is described for C, how to do this. The following example hides/deletes all command line arguments:

#include <string.h>

int main(int argc, char **argv)
{
    // process command line arguments....

    // hide command line arguments
    if (argc > 1) {
        char *arg_end;    
        arg_end = argv[argc-1] + strlen (argv[argc-1]);
        *arg_end = ' ';
    }

    // ...
}

Look also at https://stackoverflow.com/questions/724582/hide-arguments-from-ps and https://stackoverflow.com/questions/3830823/hiding-secret-from-command-line-parameter-on-unix .