Tags

• Tags in grep may not be as obvious to use. However, here is an example.

echo abc123abc | grep "\(abc\)123\1“

• Think of tags as the STR or M+ and RCL keys on your calculator

• STR/M+ as a regex \(...\) \(...\)

• RCL as a regex \1 \2

• You can have up to 9 "memories" or tags in any one regex.