Search a file for a key word using grep

[buxtonicer1]

Hi,
Is it possible to search a file for a key word or a line that contains a key word. I know you can use the grep option but how do you invoke an exact match. I only want an exact match to return. However, it does seem straight forward though. As always with UNIX, the learning curve is steep.

 

[KenCunningham]

You could use the -v option to exclude whatever spurious matches you wish:

grep word filename | grep -v 'exclusion' | grep -v 'exclusion' and so on.

 

[columb]

If you mean how do you include 'text' but exclude, for example, 'context' then that's a little more complex. A starting point is to use

grep " text " filename

but, and it's a big but, this will miss the word text when
[ol]
[li]It's at the beginning of a line[/li]
[li]It's at the end of a line[/li]
[li]It's at the end of a sentence[/li]
[li]It's in quotes[/li]
[li]It's got a tab in front of it or behind it[/li]
[li]There are plenty more exceptions but I'm sure you're getting the point[/li]
[/ol]
If you really want/need to do this you need to reach for a more powerful tool such as awk or perl. The code

perl -e 'while (<>){/\btext\b/ and print;}' filename

would do the trick but perl - and awk - are whole separate subjects of their own.

Ceci n'est pas une signature
Columb Healy

 

[feherke]

Hi

For example my [tt]grep[/tt] can handle it.

-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 charac-­
ter. Similarly, it must be either at the end of
the line or followed by a non-word constituent
character. Word-constituent characters are let-­
ters, digits, and the underscore.

It is GNU [tt]grep[/tt] 2.5.1.

Feherke.

http://rootshell.be/~feherke/

 

[feherke]

Hi

By the way, some [tt]grep[/tt]s can match the boundary like in your [tt]perl[/tt] code :

grep '\b[green][i]text[/i][/green]\b' /input/file

Or can do a messy somehow equivalent :

grep '\([^[:alnum:]_]\|^\)[green][i]text[/i][/green]\([^[:alnum:]_]\|$\)' /input/file

[gray]# or[/gray]

grep -E '([^[:alnum:]_]|^)[green][i]text[/i][/green]([^[:alnum:]_]|$)' /input/file

By the way, you have a [tt]while[/tt] in your [tt]perl[/tt] code which could be done automatically by the interpreter :

perl -ne 'print if /\b[green][i]text[/i][/green]\b/' /input/file

[gray]# or[/gray]

perl -pe '/\b[green][i]text[/i][/green]\b/||($_="")' /input/file

Feherke.

http://rootshell.be/~feherke/