Secure Shell Getting started with Secure Shell Connecting from script using password

Example

When you really need to script ssh connection, piping the password into the ssh command does not work (echo passw0rd | ssh host). It is because the password is not read from standard input, but directly from TTY (teleprinter, teletypewriter, Teletype for historical reasons).

But there is sshpass tool which works around this problem. It can read the password from parameter, file or environment variable. But note that none of these options does not satisfy the security requirements for a passwords!

$ sshpass -p passw0rd ssh host
$ sshpass -f /secret/filename ssh host
$ SSHPASS=passw0rd sshpass -e ssh host

The command line options can be seen by other users in ps (during runtime it is masked, but not during start time and you can't rely on it):

... 23624  6216 pts/5    Ss   Aug30   0:00  \_ /bin/bash
... 12812  1988 pts/5    S+   08:50   0:00  |   \_ sshpass -p passw0rd ssh host
... 45008  5796 pts/15   Ss+  08:50   0:00  |       \_ ssh host

Note, that environemnet variables of a process are also accessible by other processes on the system using /proc/PID/environ file.

Finally, storing the password in the file might look like the best possible idea, but still using keys as described in the other examples is preferred way to use ssh.