It took me ages to learn bash redirection properly, and I still have to concentrate sometimes to keep my &s and my >s straight. Here's the lowdown in case you, too, have intermittent brain failure on this one.

Bash has three standard file descriptors: stdin, stdout and stderr, which refer respectively to input, output and error output. By default, all of these are directed to the terminal, so all input comes from the terminal, and all output (regular and error) will go to the terminal.

You're probably already familiar with redirecting stdin and stdout:

process.pl < datain.txt > dataout.txt

/etc/init.d/apache2 2> errors.txt

Read the rest of this Linux BASH story at ServerWatch.com