Linux Redirection & Pipes

 1. Ability to control input and output
Input redirection '<':
 1. cat < 123.txt
Note: Use input redirection when program does NOT default to file as input
Output redirection '>':
 1. cat 123.txt > onetwothree.txt
Note: Default nature is to:
 1. Clobber the target file
 2. Populate with information from input stream

Append redirection '>>':
 1. cat 123.txt >> numbers.txt - creates 'numbers.txt' if it doesn't exist, or appends if it does
 2. cat 456.txt >> numbers.txt

Pipes '|':
Features: Connects the output stream of one command to the input stream of a subsequent command
 1. cat 123.txt | sort
 2. cat 456.txt 123.txt | sort
 3. cat 456.txt 123.txt | sort | grep 3