Unix / Shell Tricks

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Find your public IP in the shell curl -s http://checkip.dyndns.org | sed ’s/[a-zA-Z/<> :]//g’

Simple but effective.

Chaining commands Using ; will run the next command even if the first one fails (exit code is -1)

cd some_folder; tar -c .

Using && 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.