regex - pattern for matching a filepath -

can please tell me grep pattern matching following filepath:

../any_directoryname/filename.txt

i know filename. any_directoryname keeps on changing.

thanks in advance,

regards

john

try this:

\.\./[^/]+/filename.txt

this assumes 1 directory. if can more that, try

\.\./[^\r\n]+/filename.txt

Expalin