% time /usr/local/plan9/bin/grep -c . /tmp/x
39536274
real 0m1.731s
user 0m1.568s
sys 0m0.158s
% time /usr/bin/egrep -c . /tmp/x
39536274
real 0m9.798s
user 0m9.644s
sys 0m0.153s
%
% time /usr/local/plan9/bin/grep -c '(ab|cd)' /tmp/x
1023171
real 0m1.719s
user 0m1.560s
sys 0m0.158s
% time /usr/bin/egrep -c '(ab|cd)' /tmp/x
1023171
real 0m32.692s
user 0m32.525s