Subject: Re: bug#7076: Command required

From: Bob Proulx <[email-masked]>
Date: Mon, 20 Sep 2010 15:21:18 -0600

Imran Shoaib wrote:
> How can we extract few characters from second or third line of a text
> file using cut command of Linux OS?

In the future please send discussion questions concerning the
coreutils to the coreutils mailing list instead of the bug-coreutils.
The bug-coreutils mailing list is for bug reports only and every email
message opens up a bug in the bug tracking system.  I am closing this
bug report but discussion may continue.  Thanks.

A good place for general help questions is [email-masked].

> For example: to get 7-10 characters from 3rd line of a text file is
> required, what can be the command?

I would use sed for this.  Don't print by default (-n) and then print
the 3rd line.

  $ printf "1234567890\n1234567890\n1234567890\n" | sed -n 3p

If you want specific characters then you can delete the unwanted
ones.  This is a contrived example:

  $ printf "1234567890\n1234567890\n1234567890\n" | sed -n '3{s/^..\(..\).*/\1/;p;}'

Or you can chain commands together.  Print only the third line to a
command that pulls apart fields.

  $ printf "11 12 13\n21 22 23\n31 32 33\n" | awk 'NR==3{print$2}'
  32

  $ printf "11 12 13\n21 22 23\n31 32 33\n" | awk 'NR==3{print $2, $3}'
  32 33

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Bob