Show all the file up to the match with extra lines

Question

I want to print the head of a file up to a match and some lines after the match.

I know that you can use sed '/PATTERN/q' FILE to print the file until the pattern. And sed 10q FILE top print the first 10 lines.

Starting with this file:

lorem
ipsum
dolor
sit
amet
consectetur
adipiscing
elit

If my pattern is dolor and I want 2 more lines the output will be:

lorem
ipsum
dolor
sit
amet

Is this a way to merge this two commands ?

Alos, is is possible to do the same for the end of the file (ie to print the tail of the file with some lines before the match) ?

If I keep the first file with the pattern amet and the 2 lines before the match, the output will be:

dolor
sit
amet
consectetur
adipiscing
elit

source: https://unix.stackexchange.com/a/11306/117394

Possible duplicate of [How to combine multiple sed commands into one](https://stackoverflow.com/questions/39130560/how-to-combine-multiple-sed-commands-into-one) — Inian, Mar 30 '18 at 13:00
[edit] your question to include concise, testable sample input and expected output so we can help you come up with the best solution to your problem. — Ed Morton, Mar 30 '18 at 13:06
@Inian I have edited my question to add an example of what I want. — jmlemetayer, Mar 30 '18 at 13:11

Ed Morton · Accepted Answer · 2018-03-30T13:38:31.633

1

$ awk '1; /dolor/{c=3} c&&(!--c){exit}' file
lorem
ipsum
dolor
sit
amet

$ tac file | awk '1; /amet/{c=3} c&&(!--c){exit}' | tac
dolor
sit
amet
consectetur
adipiscing
elit

See https://stackoverflow.com/a/17914105/1745001 for how to find lines around a regexp match with awk.

edited Mar 30 '18 at 13:38

answered Mar 30 '18 at 13:32

Ed Morton

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jmlemetayer · Answer 2 · 2018-03-30T13:25:43.637

0

Found a solution with awk:

awk '
{
    if (matched == 0) {
        print;
    } else if (lines > 0) {
        lines--;
        print;
    }
}

/dolor/ {
    matched = 1;
    lines = 2;
}' test

Inspired by: https://stackoverflow.com/a/5316718/2893600

edited Mar 30 '18 at 13:25

answered Mar 30 '18 at 13:21

jmlemetayer

4,774
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You might want to take a look at https://stackoverflow.com/a/17914105/1745001 for how to find lines before/after matches in awk. – Ed Morton Mar 30 '18 at 13:27
1

@EdMorton Thanks for the file. It is very helpful! – jmlemetayer Mar 30 '18 at 13:37

score 0 · Answer 3 · answered Mar 30 '18 at 15:08

0

With gnu sed

2 more lines after the pattern

sed '/^dolor/!b;N;N;q' infile

2 more lines before the pattern

sed 'N;:A;N;/\namet/!{s/[^\n]*\n//;bA };:B;N;bB' infile

answered Mar 30 '18 at 15:08

ctac_

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Show all the file up to the match with extra lines

3 Answers3