Re: [PLUG] xargs guide

Ah, so grep -F is still supported, they're just deprecating the aliases?

I can tell you from personal experience that `LC_ALL=C fgrep ...` (or, I suppose `LC_ALL=C grep -F ...`) is much faster by several orders of magnitude. Try a side by side comparison on something like a 50 gig database-dump text file. `LC_ALL=C` also sets the locale to be simple, instead of UTF-8. I'd be lying if I said I understood everything about locales, but the `C` locale is a special locale for computers designed to be extremely simple.

Good catch on the deprecation, another habit to break now...

Regards,

-Tim

On Fri, Jul 31, 2015 at 10:26 AM, Walt Mankowski <waltman@pobox.com> wrote:

The manpage for GNU's grep says fgrep is deprecated:

In addition, the variant programs egrep, fgrep and rgrep are the
same as grep -E, grep -F, and grep -r, respectively. These variants
are deprecated, but are provided for backward compatibility.

I'm not seeing a noticeable difference in speed using -F in my limited
testing -- searching for "nan" in 75MB of JSON spread over 25 files --
but it seems like a good idea and I'll try to remember to use it in
the future.

On Thu, Jul 30, 2015 at 04:07:39PM -0400, Tim Allen wrote:
> If you're not doing pattern matching, it is a good habit to use:
>
> fgrep -rl --include="*.php" 'malware url on google malware report'
> /path/to/dirs/with/php_files
>
> fgrep is exactly the same as grep -F. If you're doing a search on a deep
> directory path with lots of files, not having pattern matching can increase
> the speed significantly. It is a hard habit to break after years of
> grepping (I'm guilty as charged), but I'm getting better about it, as it is
> the exception that I'm doing any pattern matching in my greps rather than
> the rule.
>
> Regards,
>
> -Tim
>
> On Thu, Jul 30, 2015 at 11:43 AM, <bergman@merctech.com> wrote:
>
> > In the message dated: Thu, 30 Jul 2015 00:28:51 -0400,
> > The pithy ruminations from Michael Lazin on
> > <Re: [PLUG] xargs guide> were:
> > => I also use xargs, for example, to find a malware string in php code,
> > like
> > => "find . -name '*,php' | xargs grep 'malware url on google malware
> > report' | cut -d: -f1"
> >
> > Ick.
> >
> > With a suitably modern version of grep:
> >
> > grep -rl --include="*,php" 'malware url on google malware report'
> > /path/to/dirs/with/php_files
> >
> > Mark
> >
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