Lecture 7 (Regular Expressions) Exercise answers:

Slide 6:
      egrep "\<C\>" ideas.txt

      egrep -i "^Act\>|^Scene" hamlet.txt
      egrep -i "(^Act\>|^Scene) [IV]+\." hamlet.txt


Slide 8:
      egrep "\^_?\^" chat.txt  


Slide 10:
      egrep "\<[ABCDF][+\-]?$" 143.txt


Slide 11:
      egrep "\(206\) [0-9]{3}-[0-9]{4}" faculty.html 


Slide 14:

      # Simple search and replace
      sed -r "s/The/The Super Awesome/g" movies.txt

      # Only at beginning of line.
      sed -r "s/^The/The Super Awesome/g" movies.txt

      # Put year first and sort by year
      sed -r "s/^(.*)\(([0-9]{4})\)/\2 \1/g" movies.txt | sort

      # Now put it back in original format:
      sed -r "s/^(.*) \(([0-9]{4})\)/\2 \1 /g" movies.txt | sort | sed -r "s/([0-9]{4}) (.*)/\2(\1)/g"


Slide 15:
      sed -r "s/([0-9]{3})-([0-9]{4})/(206) \1\.\2/g" faculty.html
      

Slide 17:
      #!/bin/bash

      YEAR=2011
      for FILE in `cat files.txt`; do
      	    sed -r "s#([0-9]{1,2})/([0-9]{1,2})#\1/\2/$YEAR#g" $FILE
      done