CODEWITHSUNDEEP
linuxperlsshsystem
Guido Pujadas
Guido Pujadas

Reputation: 33

call "ssh" in system function in perl

i have a question related to connecting via ssh with "system()" function in perl.

in my perl script i want to connect via ssh to another ip, run a command and return its value or redirect result value to a file.

system ("su - anotherUSer ; ssh someUsername@someIpAddress");

(i change my username so that i am not asked for a password)

when i execute this only line it changes the username correctly but not connects via ssh. In other words, the second part of the system call is not done (or is done but not reflected on the terminal).

If i enter mannualy to the server where this script executes and run this two commands, i can run them without errors.

When i run "exit" command to logout my anotherUser user an error raises:

(ssh: "username"."ip": node name or service name not known)

I also tested it escaping '@' and '.'

system ("su - anotherUSer ; ssh someUsername\@number\.number\.number\.number");

in this case when i run the "exit" command, it askes for the password(Remember that i swiched users so that password could be ommited).

I hope you understand my problem.

Thanks!!!

Upvotes: 0

Views: 616

Answers (1)

ikegami
ikegami

Reputation: 386501

You're telling the wrong shell to execute ssh.

You spawn a shell and ask it to execute two commands, su and ssh. It first spawns su, which launches another shell. You didn't tell this new shell to do anything, so it waits for input. When it finally exits, the first shell executes the second command, ssh.

Use:

system("su -c 'ssh someUsername@someIpAddress' - anotherUSer");

But that's nasty! Why not just set up a key for the current user instead of becoming anottherUSer to use theirs?

Upvotes: 4

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