LinuxQuestions.org - grep a single word...not two!

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- - grep a single word...not two! (https://www.linuxquestions.org/questions/linux-newbie-8/grep-a-single-word-not-two-4175467215/)

Drigo

06-24-2013 04:20 PM

grep a single word...not two!

So if I use:

$<my command> | grep dim4
#I get to options:

Output :
dim4 42
pixdim4 1.0000000000

But I would like just the 'dim4 ' line to appear without the pixdim4 line....like this:

$<my command> | grep dim4
#I want the output just with the first line:

Output:
dim4 42

How can i make it work?
Thanks in advance!

druuna

06-24-2013 04:29 PM

If dim is always at the beginning of the line try:

Code:

grep "^dim4"

And if it is not:

Code:

grep "\<dim4\>"

linuxCode

06-24-2013 04:37 PM

try this

<my command> | grep -w 'dim4'

eklavya

06-25-2013 12:36 AM

You can try this too.

Code:

<my command> | grep "\bdim4"

Madhu Desai

06-25-2013 12:58 AM

Quote:

Originally Posted by Drigo (Post 4977809)

But I would like just the 'dim4 ' line to appear without the pixdim4 line....like this:

#I want the output just with the first line:

If you just want to search for first line, then there is no need for grep.

Code:

$ <command> | head -n1

But if you are referring to return only first hit, then, any of these will work

Code:

$ <command> | grep -w -m1 'dim4'

$ <command> | grep -m1 '\<dim4\>'

$ <command> | grep -m1 '\bdim4\b'

shivaa

06-25-2013 01:09 AM

No need to make it complecated. Just use -w option to grep some specific regexp. From manual of grep:

Quote:

-w, --word-regexp
Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a non-word constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word-constituent characters are letters, digits, and the underscore.

Code:

~$ <my_command> | grep -w 'dim4'

Drigo

06-26-2013 12:34 PM

Great!!! The fist two posts worked :)
This post and you guys are great!

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