|Home||Switchboard||Unix Administration||Red Hat||TCP/IP Networks||Neoliberalism||Toxic Managers|
May the source be with you, but remember the KISS principle ;-)
Bigger doesn't imply better. Bigger often is a sign of obesity, of lost control, of overcomplexity, of cancerous cells
pcregrep - a grep with Perl-compatible regular expressions.
pcregrep [options] [long options] [pattern] [path1 path2 ...]
pcregrep searches files for character patterns, in the same way as other grep commands do, but it uses the PCRE regular expression library to support patterns that are compatible with the regular expressions of Perl 5. See pcrepattern for a full description of syntax and semantics of the regular expressions that PCRE supports.
Patterns, whether supplied on the command line or in a separate file, are given without delimiters. For example:
pcregrep Thursday /etc/motd
If you attempt to use delimiters (for example, by surrounding a pattern with slashes, as is common in Perl scripts), they are interpreted as part of the pattern. Quotes can of course be used on the command line because they are interpreted by the shell, and indeed they are required if a pattern contains white space or shell metacharacters.
The first argument that follows any option settings is treated as the single pattern to be matched when neither -e nor -f is present. Conversely, when one or both of these options are used to specify patterns, all arguments are treated as path names. At least one of -e, -f, or an argument pattern must be provided.
If no files are specified, pcregrep reads the standard input. The standard input can also be referenced by a name consisting of a single hyphen. For example:
pcregrep some-pattern /file1 - /file3
By default, each line that matches the pattern is copied to the standard output, and if there is more than one file, the file name is output at the start of each line. However, there are options that can change how pcregrep behaves. In particular, the -M option makes it possible to search for patterns that span line boundaries.
Patterns are limited to 8K or BUFSIZ characters, whichever is the greater. BUFSIZ is defined in <stdio.h>.
If the LC_ALL or LC_CTYPE environment variable is set, pcregrep uses the value to set a locale when calling the PCRE library. The --locale option can be used to override this.
This terminate the list of options. It is useful if the next item on the command line starts with a hyphen but is not an option. This allows for the processing of patterns and filenames that start with hyphens.
Output a brief help message and exit.
The environment variables LC_ALL and LC_CTYPE are examined, in that order, for a locale. The first one that is set is used. This can be overridden by the --locale option. If no locale is set, the PCRE library's default (usually the "C" locale) is used.
The majority of short and long forms of pcregrep's options are the same as in the GNU grep program. Any long option of the form --xxx-regexp (GNU terminology) is also available as --xxx-regex (PCRE terminology). However, the --locale, -M, --multiline, -u, and --utf-8 options are specific to pcregrep.
There are four different ways in which an option with data can be specified. If a short form option is used, the data may follow immediately, or in the next command line item. For example:
-f/some/file -f /some/file
If a long form option is used, the data may appear in the same command line item, separated by an equals character, or (with one exception) it may appear in the next command line item. For example:
--file=/some/file --file /some/file
Note, however, that if you want to supply a file name beginning with ~ as data in a shell command, and have the shell expand ~ to a home directory, you must separate the file name from the option, because the shell does not treat ~ specially unless it is at the start of an item.
The exception to the above is the --colour (or --color) option, for which the data is optional. If this option does have data, it must be given in the first form, using an equals character. Otherwise it will be assumed that it has no data.
It is possible to supply a regular expression that takes a very long time to fail to match certain lines. Such patterns normally involve nested indefinite repeats, for example: (a+)*\d when matched against a line of a's with no final digit. The PCRE matching function has a resource limit that causes it to abort in these circumstances. If this happens, pcregrep outputs an error message and the line that caused the problem to the standard error stream. If there are more than 20 such errors, pcregrep gives up.
Exit status is 0 if any matches were found, 1 if no matches were found, and 2 for syntax errors and non-existent or inacessible files (even if matches were found in other files) or too many matching errors. Using the -s option to suppress error messages about inaccessble files does not affect the return code.
University Computing Service
Cambridge CB2 3QG, England.
Last updated: 23 January 2006
Copyright (c) 1997-2006 University of Cambridge.
Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers : Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism : The Iron Law of Oligarchy : Libertarian Philosophy
War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda : SE quotes : Language Design and Programming Quotes : Random IT-related quotes : Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce : Bernard Shaw : Mark Twain Quotes
Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 : Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law
Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds : Larry Wall : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS : Programming Languages History : PL/1 : Simula 67 : C : History of GCC development : Scripting Languages : Perl history : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history
The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month : How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite
Most popular humor pages:
Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor
The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D
Copyright © 1996-2018 by Dr. Nikolai Bezroukov. www.softpanorama.org was initially created as a service to the (now defunct) UN Sustainable Development Networking Programme (SDNP) in the author free time and without any remuneration. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.
This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...
|You can use PayPal to make a contribution, supporting development of this site and speed up access. In case softpanorama.org is down you can use the at softpanorama.info|
The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with. We do not warrant the correctness of the information provided or its fitness for any purpose.
Last modified: March, 12, 2019