Living in the Shell #15; sed (Text Stream Editor) (Part 2)

sed 🖊️

Edits streams by applying commonly used modifications.

Replace substring s

cat some-file.txt | sed 's/me/you/g'

Replaces all occurrences of "me" with "you".

Replace pattern s

echo "about\nabuse\namount" | sed 's/a\(\w*\?\)\w/\1/g'

bou
bus
moun

\1 refers to the first captured group.

Transform to lowercase \L

echo "HELLO THERE\nHI THERE\nGOODBYE" | sed 's/H\w*/\L&/g'

hello There
hi There
GOODBYE

• Transforms words beginning with "H" to lowercase.
• & is the place holder for "entire match".

Transform to uppercase \U

cat some-file.txt | sed 's/.*/\U&/g'

Transforms all letters into uppercase.