Using \lstinputlisting to include a file but only certain lines or line ranges

Each "listing" environment understands the firstline and lastline keys:

\lstinputlisting[firstline=300,lastline=500]{file.cc}

listings supports line ranges not only with firstline and lastline (see egregs answer) but even with linerange={<first1>-<last1>,<first2>-<last2> …}. Note, that first2 has to be greater than last1 and so on. So

\lstinputlisting[linerange={1-4,7-9}]{file.cc}

would be valid but

\lstinputlisting[linerange={7-9,1-4}]{file.cc}% Don't do this!!!

is not allowed!

For more information see section 4.3.3 "The printed range" at the listings manual.

As an addendum to egreg's answer: If you are typesetting line numbers and want these numbers to reflect the physical line numbers, the firstnumber key comes at your rescue:

\lstinputlisting[numbers=left,firstnumber=300,firstline=300,lastline=500]{file.cc}