### Awk ###

 1. Field/Column processor
 2. Supports egrep-compatible (POSIX) RegExes
 3. Can return full lines like grep
 4. Awk runs 3 steps:
  a. BEGIN - optional
  b. Body, where the main action(s) take place
  c. END - optional
 5. Multiple body actions can be executed by separating them using semicolons. e.g. '{ print $1; print $2 }'
 6. Awk, auto-loops through input stream, regardless of the source of the stream. e.g. STDIN, Pipe, File

Usage:
 1. awk '/optional_match/ { action }' file_name | Pipe
 2. awk '{ print $1 }' grep1.txt
Note: Use single quotes with awk, to avoid shell interpolation of awk's variables
 3. awk '{ print $1,$2 }' grep1.txt
Note: Default input and output field separators is whitespace
 4. awk '/linux/ { print } ' grep1.txt - this will print ALL lines containing 'linux'
 5. awk '{ if ($2 ~ /Linux/) print}' grep1.txt
 6. awk '{ if ($2 ~ /8/) print }' /var/log/messages - this will print the entire line for log items for the 8th
 7. awk '{ print $3 }' /var/log/messages | awk -F: '{ print $1}'