Re: grep extremely slow on OSX

[Jim Meyering]

Titus von der Malsburg wrote:
> When I do a simple grep on a 50Mb file with ~1.3 million lines, it
> takes 2s on Linux (Ubuntu karmic with stock kernel, 2.6.31-17) and
> ~12min on OSX (v. 10.5.8):
>
>   grep '^[0-9]'  < file.dat > /dev/null
>
> ~1.2 million lines actually begin with a number.  Both systems run on
> a Core 2 Duo CPU at 2.2 GHz and have 2GB of RAM. On both systems, I
> use utf-8 encoding (en_US.UTF-8).

Thanks for the report.
I can confirm that something is very wrong:

In the C/POSIX locale, Fedora 12's grep is quick:
(this is on a tmpfs file system)

  $ yes 123456789012345678901234567890|head -n1300000 > in
  $ env time grep '^[0-9]' in > /dev/null
  0.15user 0.01system 0:00.16elapsed 97%CPU (0avgtext+0avgdata 0maxresident)k
  200inputs+0outputs (1major+213minor)pagefaults 0swaps

But in a UTF locale, it's incredibly slow:

  $ LC_ALL=en_GB.UTF-8 env time grep '^[0-9]' in > /dev/null

I ran out of patience and interrupted the above after a couple of minutes.