[hjl@gnu-34 rrs]$ time /bin/egrep -v "^[ \t]*$" pr15242.i  > x.c 

real	0m10.490s
user	0m10.484s
sys	0m0.004s
[hjl@gnu-34 rrs]$ time ./egrep -v "^[ \t]*$" pr15242.i  > x.c 

real	0m0.039s
user	0m0.034s
sys	0m0.003s
[hjl@gnu-34 rrs]$ /bin/egrep --version
GNU grep 2.5.3

Copyright (C) 1988, 1992-2002, 2004, 2005  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[hjl@gnu-34 rrs]$ ./egrep --version
egrep (GNU grep) 2.5.1

Copyright 1988, 1992-1999, 2000, 2001 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
[hjl@gnu-34 rrs]$