cat ideas.txt 
egrep "C" ideas.txt 
egrep "C\>" ideas.txt 
egrep "\<C\>" ideas.txt 

less hamlet.txt
egrep "act" hamlet.txt 
egrep "Act" hamlet.txt 
egrep "\<Act" hamlet.txt 
egrep -i "\<Act" hamlet.txt 
egrep -i "\<Act\>" hamlet.txt 
egrep -i "^Act\>" hamlet.txt 
egrep -i "scene" hamlet.txt 
egrep -i "^scene" hamlet.txt 
egrep -i "^Act\>|^Scene" hamlet.txt

cat chat.txt 
egrep "\^" chat.txt 
egrep "\^\^" chat.txt 
egrep "\^_\^" chat.txt 
egrep "\^.*\^" chat.txt 
egrep "(\^\^|\^_\^)" chat.txt 
egrep "\^_?\^" chat.txt 

cat 143.txt 
egrep "[ABCDF]" 143.txt 
egrep "[A-DF][+\-]?" 143.txt 
egrep "[A-DF][+\-]?$" 143.txt 

cat contact.html 
egrep "[0-9]" contact.html 
egrep "\([0-9]" contact.html 
egrep "\([0-9]{3}" contact.html 
egrep "\([0-9]{3}\)" contact.html 
egrep "\([0-9]{3}\) [0-9]{3}" contact.html 
egrep "\([0-9]{3}\) [0-9]{3}-[0-9]" contact.html 
egrep "[0-9]{3}-[0-9]{4}" contact.html 

# Replace occurences of Jones with Anderson
# Replace Jones every time it occurs on a line.
sed -r "s/Jones/Anderson/g" names.txt
# Only replace the first occurence of Jones on a line.
sed -r "s/Jones/Anderson/" names.txt

# Swap order of first and last names:
sed -r "s/([A-Za-z]+), ([A-Za-z]+)/\2 \1/g" names.txt
# Demonstrate parenthesis inside of parenthesis:
sed -r "s/(([A-Za-z]+), ([A-Za-z]+))/Last: \3 First: \2 Original: \1/g" names.txt

# Match lines with the same name separated by a comma and space: name, name
egrep "([A-Za-z]+), \1" names.txt

# Put a dot where the dash is currently.
sed -r "s/([0-9]{3})-([0-9]{4})/\1\.\2/g" contact.html 
# Send the output to a file (can't use the same file name as source and dest)
sed -r "s/([0-9]{3})-([0-9]{4})/\1\.\2/g" contact.html > contact2.html