How to delete specific lines (2n+3 line, n=0,1,2...296) in a file?

phamnu · #1 02-09-2013

Dear everyone,
I have a file with 900 lines (there is only numbers in one line, no string),
I only need the lines 2+3n (n=0,1...296), i.e line 2, 5, 8, 11...888.
I tried google but only the results such as how to delete all the odd lines or all the even lines with 'awk' command.
Thanks in advance.

elixir_sinari · #2 02-09-2013

Assuming that you need those particular lines to be printed:

Code:

awk '!((NR-2)%3)' file

phamnu · #3 02-09-2013

Quote:

Originally Posted by elixir_sinari

Assuming that you need those particular lines to be printed:

Code:

awk '!((NR-2)%3)' file

You are great!!!

RudiC · #4 02-09-2013

Code:

$ sed -n '2~3p' file
2
5
8

bakunin · #5 02-09-2013

Quote:

Originally Posted by RudiC

Code:

$ sed -n '2~3p' file

Not sure this is POSIX compliant, though...

Not sure either, but the AIX sed doesn't understand it. I suppose it is a GNU extension.

I hope this helps.

bakunin

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The Following 2 Users Say Thank You to elixir_sinari For This Useful Post:
alister (02-09-2013), phamnu (02-09-2013)