#!/bin/bash# remote.bash: Using ssh.# This example by Michael Zick.# Used with permission.#   Presumptions:#   ------------#   fd-2 isn't being captured ( '2>/dev/null' ).#   ssh/sshd presumes stderr ('2') will display to user.##   sshd is running on your machine.#   For any 'standard' distribution, it probably is,#+  and without any funky ssh-keygen having been done.# Try ssh to your machine from the command line:## $ ssh $HOSTNAME# Without extra set-up you'll be asked for your password.#   enter password#   when done,  $ exit## Did that work? If so, you're ready for more fun.# Try ssh to your machine as 'root':##   $  ssh -l root $HOSTNAME#   When asked for password, enter root's, not yours.#          Last login: Tue Aug 10 20:25:49 2004 from localhost.localdomain#   Enter 'exit' when done.#  The above gives you an interactive shell.#  It is possible for sshd to be set up in a 'single command' mode,#+ but that is beyond the scope of this example.#  The only thing to note is that the following will work in#+ 'single command' mode.# A basic, write stdout (local) command.ls -l# Now the same basic command on a remote machine.# Pass a different 'USERNAME' 'HOSTNAME' if desired:USER=${USERNAME:-$(whoami)}HOST=${HOSTNAME:-$(hostname)}#  Now excute the above command line on the remote host,#+ with all transmissions encrypted.ssh -l ${USER} ${HOST} " ls -l "#  The expected result is a listing of your username's home#+ directory on the remote machine.#  To see any difference, run this script from somewhere#+ other than your home directory.#  In other words, the Bash command is passed as a quoted line#+ to the remote shell, which executes it on the remote machine.#  In this case, sshd does  ' bash -c "ls -l" '   on your behalf.#  For information on topics such as not having to enter a#+ password/passphrase for every command line, see#+    man ssh#+    man ssh-keygen#+    man sshd_config.exit 0