cat file.txt | sed -e /<opening tag>/d -e /<closing tag>/G | sed -e '/./{H;$!d;}' -e 'x;/<string to search>/!d;'

Multi line grep using sed and specifying open/close tags

Working with log files that contains variable length messages wrapped between open and close tags it may be useful to filter the messages upon a keyword. This works fine with GNU sed version 4.2 or higher, so pay attention to some unix distros (solaris, hp-ux, etc.). Linux should be ok.
Sample Output
The command:
cat file.txt | sed -e /^$/d -e /++-/G | sed -e '/./{H;$!d;}' -e 'x;/Lorem/!d;'

Will print the message:

^$
Lorem ipsum dolor sit amet,
consectetur adipiscing elit.
++-

But not:

^$
Vestibulum fermentum molestie nunc a interdum.
++-

2
By: EBAH
2010-11-04 10:31:15

1 Alternatives + Submit Alt

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