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Cover image for Living in the Shell #15; sed (Text Stream Editor) (Part 2)
Babak K. Shandiz
Babak K. Shandiz

Posted on • Originally published at babakks.github.io on

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

Replace pattern s

echo "about\nabuse\namount" | sed 's/a\(\w*\?\)\w/\1/g'
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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'
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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'
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Transforms all letters into uppercase.

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