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Using grep and zgrep then display the next few lines


 
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# 1  
Old 08-25-2010
Using grep and zgrep then display the next few lines

Hello everyone.
I would like to know if I can use grep or zgrep to search for a particular pattern then print the x number of lines after the pattern was found.
Lets say for example a pattern was found on line 3, I wanted the output to show lines 3, 4 and 5.

Thanks!
# 2  
Old 08-25-2010
Hi.

Does your grep or zgrep have the -A option?

If not, I would use awk.

i.e.

Code:
$ awk '$0 ~ S || C { C++ } C-1 > A { exit } C' S="some_regex" A=2 file1

# 3  
Old 08-25-2010
Nope. The -A option is not available.
I tried the awk command and it works but it will only yeild one result.
# 4  
Old 08-25-2010
Smilie

I don't always create as much test data as I should!

Code:
$ awk '$0 ~ S || C { C++ } C-1 > A { C = 0 } C' S="some_regex" A=2 file1

This User Gave Thanks to Scott For This Post:
# 5  
Old 08-25-2010
Cool!
You're the man!
Thanks!
# 6  
Old 08-26-2010
Quote:
Originally Posted by scottn
Code:
$ awk '$0 ~ S || C { C++ } C-1 > A { exit } C' S="some_regex" A=2 file1

Quote:
Originally Posted by scottn
Code:
$ awk '$0 ~ S || C { C++ } C-1 > A { C = 0 } C' S="some_regex" A=2 file1

I don't see any difference between these two command even if my input file has repetitive regular expression pattern. Both just yield only one result. scottn! it would be great if you could shed the light on this?
# 7  
Old 08-26-2010
Quote:
Originally Posted by royalibrahim
I don't see any difference between these two command even if my input file has repetitive regular expression pattern. Both just yield only one result. scottn! it would be great if you could shed the light on this?
Which OS are you using? Can you demonstrate that?

Code:
$ jot -wx 3; echo blah; jot -wy 3; echo more blah; jot -wz 3 10
x1
x2
x3
blah
y1
y2
y3
more blah
z10
z11
z12

$ r | awk '$0 ~ S || C { C++ } C-1 > A { C = 0 } C' S="blah" A=2
jot -wx 3; echo blah; jot -wy 3; echo more blah; jot -wz 3 10
blah
y1
y2
more blah
z10
z11

 

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