Getting a string from a text file

What would be the best way to open a text file, find a string, delete it, perform an action then add the string back to the text file? !!!

ie

open text file
find "wibble"
if it exists - delete it
close text file

perform some action

open text file
add "wibble"
close text file

Any ideas people?
Simon

I didn't test it but try this out:

'This will open a file:

Open filename For Binary As #1
File = Space(LOF(#1))
Get #fnum, , filevar
Close #1


'And this will search it for the string and remove it:

a=instr(filevar,string)
filevar=left(filevar,a-1) & mid(filevar,a+len(string))

'This will put it back in the file

Open filename For Binary As #1
Put #1, , filevar
Close #1

'This will add string

Open filename for append as #1
Print#1, string;
close #1