File Streams

1. standard input stdin 0

2. standard output stdout 1

3. standard error stderr 2

I/O Redirection

Change were output goes and input comes from.

Operator	Action
>	Redirect to file
>>	Append to file
2>	Redirect stderr to file
2>&1	Redirect stderr to file descriptor 1, if no file then default is to screen
&>,$>>	Redirect stdout and stderr to file
2> /dev/null	Dispose of stderr