Newsgroups: news.software.b Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!ox.com!ox.com!emv From: emv@ox.com (Ed Vielmetti) Subject: Re: egrep hazardrous to your system's cnews health In-Reply-To: res@colnet.uucp's message of Sat, 11 May 1991 04:03:14 GMT Message-ID: Sender: usenet@ox.com (Usenet News Administrator) Organization: OTA Limited Partnership, Ann Arbor MI. References: <1991May11.040314.15393@colnet.uucp> Date: Sun, 12 May 1991 20:35:51 GMT > egrep and C news performance there are a number of programs out there which go by the name of egrep, perform roughly the same function, and whose performance differs measurably depending on system speed, available memory, and the nature of the data to be grep'd for. your best bet would be to get an egrep that uses the Henry Spencer regexp library or one of its derivatives; that would probably be substantially better than the egrep that shipped with your Unix PC. I'll have to check on the pedigree of the gnu 'egrep', it may also be suited to your needs. the other thing to note in the particular example is that it makes very conservative assumptions (for portablility considerations, no doubt) on the function of your stock utilities. you could save an awk invocation if your wc supports the '-l' flag, since "wc -l" is the same as the "wc | awk '{print $1}'" for modern versions of wc. there may well be other constructs which you could characterize, isolate, and recode for efficiency on your own system. C news does not ship with its own versions of sh, awk, ls, egrep, wc, tr, sed, and cat; it is assumed that the vendor versions will be good enough to suffice. the existing shell scripts have to work around the limitations of many known deficiences in these programs to be reasonably portable. There is enough consistency in the construction of C news shell idioms that it's well within reason to look at methodically replacing them with special purpose programs or more precisely tailored shell constructs; I'd expect that the UUNET funding of further C news development will have some of this in mind. -- Edward Vielmetti, vice president for research, MSEN Inc. emv@msen.com "(6) The Plan shall identify how agencies and departments can collaborate to ... expand efforts to improve, document, and evaluate unclassified public-domain software developed by federally-funded researchers and other software, including federally-funded educational and training software; " "High-Performance Computing Act of 1991, S. 272"