CODEWITHSUNDEEP
sed
user1246172
user1246172

Reputation: 1105

sed delete lines not containing specific string

I'm new to sed and I have the following question. In this example:

some text here
blah blah 123
another new line
some other text as well
another line

I want to delete all lines except those that contain either string 'text' and or string 'blah', so my output file looks like this:

some text here
blah blah 123
some other text as well

Any hints how this can be done using sed?

Upvotes: 90

Views: 108232

Answers (4)

Viktor Csomor
Viktor Csomor

Reputation: 21

Are you looking for the grep? Here is an example to look for different texts.

cat yourfile.txt | grep "text\|blah"

Upvotes: 1

Jonathan Leffler
Jonathan Leffler

Reputation: 753525

You want to print only those lines which match either 'text' or 'blah' (or both), where the distinction between 'and' and 'or' is rather crucial.

sed -n -e '/text/{p;n;}' -e '/blah/{p;n;}' your_data_file

The -n means don't print by default. The first pattern searches for 'text', prints it if matched and skips to the next line; the second pattern does the same for 'blah'. If the 'n' was not there then a line containing 'text and blah' would be printed twice. Although I could have use just -e '/blah/p', the symmetry is better, especially if you need to extend the list of matched words.

If your version of sed supports extended regular expressions (for example, GNU sed does, with -r), then you can simplify that to:

sed -r -n -e '/text|blah/p' your_data_file

Upvotes: 18

Avinash Raj
Avinash Raj

Reputation: 174696

You could simply do it through awk,

$ awk '/blah|text/' file
some text here
blah blah 123
some other text as well

Upvotes: 11

potong
potong

Reputation: 58371

This might work for you:

sed '/text\|blah/!d' file
some text here
blah blah 123
some other text as well

Upvotes: 127

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