Shell Programming and Scripting

Hi,

I face a problem where I have a string and I would like to use the string to filter entry from another file.

Let say, my string always change but is in a variable $filter.

I would like to match this $filter with the entry row in file B.txt let say.

File B.txt would have something like:-

$filter 2 3
$filter2 3 4
$filter4 2 4

How could I use grep or while read of the B.txt to get the entry?
Output:-

Using $filter, would get $filter 2 3
using $filter2, would get $filter2 3 4

Currently I am using while read line and I do not know how to extract the particular entry based on the string $filter.

Please help.Thanks.

-Jason

Code:

grep $filter B.txt

Or have I missunderstood you?