Simple awk Scripts

• An awk script contains patterns and actions
  awk '/sey/ { print }' /etc/passwd
  awk /sey/ /etc/passwd
  ls -l | awk '{ sum += $5; print sum; }'

• An action with no pattern applies to every line.

• An action preceded by a pattern like /sey/ is performed for each line containing the string.

• Actions are always surrounded by braces.

• Variables are always strings, but can be used as numbers.

• Initially a variable is empty with numeric value 0.

• It is easy to write an averaging script

• Special patterns BEGIN and END can be used to specify actions to perform before reading the input and after all the input has been processed.

• ls -l | awk '{ sum += $5; } END { print sum; }'

• The record number is available as NR
  awk 'NR <= 10' file