Unix Programming - unix command question

Author

unix command question

chunji08@gmail.com

2006-12-18, 7:07 pm

A text file may or may not has a keyword, Is there a way I can use a
line of unix command(s) to create a new text file, in which the line
that contains the keyword is moved to the first line ?

The one what I created is something like:
"
((cat old.txt | grep keyword ) && ( cat old.txt | grep -v keyword )) |
tee new.txt.
",

But it creates an empty "new.txt" file if the keyword does not exist in
the original file.

And idea ?

Charlie,

Chris F.A. Johnson

2006-12-18, 7:07 pm

On 2006-12-18, chunji08@gmail.com wrote:
>
> A text file may or may not has a keyword, Is there a way I can use a
> line of unix command(s) to create a new text file, in which the line
> that contains the keyword is moved to the first line ?
>
> The one what I created is something like:
> "
> ((cat old.txt | grep keyword ) && ( cat old.txt | grep -v keyword )) |
> tee new.txt.
> ",
>
> But it creates an empty "new.txt" file if the keyword does not exist in
> the original file.

line=$( grep keyword old.txt )
if [ -n "$line" ]
then
{
printf "%s\n" "$line"
grep -v keyword old.txt
} > new.txt
fi

--
Chris F.A. Johnson, author | <http://cfaj.freeshell.org>
Shell Scripting Recipes: | My code in this post, if any,
A Problem-Solution Approach | is released under the
2005, Apress | GNU General Public Licence

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