Append

To append to stream, use >>

File Discriptor

The following maps the file redirect to File descriptor:

File	File Descriptor
STDIN	0
STDOUT	1
STDERR	2

Join

To join two streams you can do thing 2>&1. This will join stderr into stdout.

Pipe

To pipe output from one program to another, use: |.

Redirect

• <: Redirect stdin
• >: Redirect stdout
• 2>: Redirect stderr