grep 'ing ' daphne.txt | egrep -vi ' (am|is|are|be|was|were|been|being) .*ing '
Actually, this search is inexact in several ways. First of all, it does not distinguish between actual gerunds and other words ending in ing. Secondly, it excludes cases where a form of be indeed precedes the gerund but is not actually related to it. Finally, the files we are working with are not formatted to have exactly one sentence per line, and grep only considers one line at a time. Therefore, linguistically speaking, this search will include examples it should have excluded. (The -C option won't help -- it only affects what grep returns, not what it matches.)
(daphne.txt is in /home/corpora/english/gutenberg/etexts00.)