Date: Thu, 12 Aug 2010 18:44:41 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-questions@FreeBSD.ORG, jacks@sage-american.com, johnl@iecc.com Subject: Re: Grepping a list of words Message-ID: <201008121644.o7CGiflh099466@lurza.secnetix.de> In-Reply-To: <20100812153535.61549.qmail@joyce.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
John Levine <johnl@iecc.com> wrote: > > > % egrep 'word1|word2|word3|...|wordn' filename.txt > > > Thanks for the replies. This suggestion won't do the job as the list of > > words is very long, maybe 50-60. This is why I asked how to place them all > > in a file. One reply dealt with using a file with egrep. I'll try that. > > Gee, 50 words, that's about a 300 character pattern, that's not a problem > for any shell or version of grep I know. > > But reading the words from a file is equivalent and as you note most > likely easier to do. The question is what is more efficient. This might be important if that kind of grep command is run very often by a script, or if it's run on very large files. My guess is that one large regular expression is more efficient than many small ones. But I haven't done real benchmarks to prove this. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd "To this day, many C programmers believe that 'strong typing' just means pounding extra hard on the keyboard." -- Peter van der Linden
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201008121644.o7CGiflh099466>