How can I capture the output of remote commands then issue more remote commands?

Question

Hi,

I am running a script where it login to a server then executes the command "passwd -n 0 -x 99999 -i -1 debug" for removing ageing of the debug user. If the user debug is not present then I want to create the user debug, change the password it, and then execute the above command for ageing.

How can I do?

Regards, vasistha

Answer 1

Use puppet.

If you really insist on doing it manually, use getent passwd debug to check whether the user exists:

if [ $(getent passwd debug | wc -l ) = 0 ]; then
    adduser debug
fi

Answer 2

From perlfunc(1):

          system LIST
               [...]
               The return value is the exit status of the program as returned
               by the "wait" call.  To get the actual exit value, shift right
               by eight (see below).

Therefore:

my $ret = system(qw/passwd -n 0 -x 99999 -i -1 debug/);
if ($ret != 0) {
  # failure handling code here
}

Answer 3

I suggest using something like Expect. It handles the interactivity for you. You can log in to the server, execute commands, inspect the output, send more input, and so on. If you are doing lots of remote server administration, it's a very handy tool to know. There's even an article about it in The Perl Review Issue 4.2 (Spring 2008)