Find your public IP in the shell curl -s http://checkip.dyndns.org | sed ’s/[a-zA-Z/<> :]//g’
Simple but effective.
; will run the next command even if the first one fails (exit code is -1)
cd some_folder; tar -c .
&& will only run the next command if the first one is okay (exit code not -1)
cd some_folder && tar -c .
Pipes are used to connect the STDOUT of one fork to the STDIN of another
(cd some_folder && tar -c .) | (cd another_folder && tar -x)
^ Here we have two forked child processes, the second one will wait until it receives input from the Pipe.