Re: Shell grep help - how to get only first occurrence of match?
Re: Shell grep help - how to get only first occurrence of match?
- Subject: Re: Shell grep help - how to get only first occurrence of match?
- From: Walter Bushell <email@hidden>
- Date: Wed, 28 Mar 2007 22:02:36 -0400
The man pages were written for people who already know what the
commands For "awk" this is more true than most Eunichs commands..
On Mar 28, 2007, at 8:18 PM, Malcolm Fitzgerald wrote:
On 29/03/2007, at 3:57 AM, Mark J. Reed wrote:
If you have columns of data separated by arbitrary amounts of
whitespace, the command you're looking for is awk, rather than grep.
awk '{print $1}' will print the first column of every line. $2 for
the second, etc.
$NF (short for "Number of Fields") for the last column, $(NF-1) for
the second-to-last, etc.
$0 is the whole line.
you can stick /pattern/ in front of the {...} block to run it only
for
lines matching that pattern, e.g.
awk '/[0-9]/ {print $1}' will print the first column of all lines
that contain a digit anywhere in the line. Note that this means
it is
never necessary to do grep | awk. :)
Wow, it's that easy. You wouldn't know it from the man page.
malcolm
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