LinuxQuestions.org - sed: pattern matching with newlines

- Linux - General (https://www.linuxquestions.org/questions/linux-general-1/)

- - sed: pattern matching with newlines (https://www.linuxquestions.org/questions/linux-general-1/sed-pattern-matching-with-newlines-706150/)

sed: pattern matching with newlines

Hi

How do I get sed to read patterns within newlines ?

Code:

sed -i 's|hello.*?world|just-hello|g' *.txt

sed -i 's|hello.*?\n.*?world|just-hello|g' *.txt

Thanks

You need to build up more than one line in either the pattern space or the hold space. Then have commands that use `\n' for the newline. The $ metacharacter will match the end of the buffer and not an embedded newline.

Use the N command to append to the pattern space, and H to append to the hold space.

Code:

cat testfile.txt

Hello World.

Hello

World.



Hello cruel world.

Code:

sed '/Hello/{ s/Hello World/Just Hello/;t

                              N;/Hello\nWorld/{N;s//Just\nHello/}

                            }' testfile.txt

Just Hello.

Just

Hello.



Hello cruel world.

Or maybe use a tool better designed for the task - perl, or even awk.