|Home||Switchboard||Unix Administration||Red Hat||TCP/IP Networks||Neoliberalism||Toxic Managers|
|May the source be with you, but remember the KISS principle ;-)|
|News||Books||See also||Recommended Links||Examples||Reference|
The wc command stands for "word count". It reads one or more input files and, by default, writes the number of newline characters, words and bytes contained in each input file to the standard output. Most often used as the last stage of pipes like ps -e | wc -l
If more than one input file is specified, a line of cumulative count(s) for each of specified files as well as is total count for all files is printed.
3 rarme.bat 11 robots.txt 334 safary.shtml 2993 strange_files.txt 1 today.lst 18 topbooks.htm 37 topupdates.htm 38 topvisited.htm 124 truncate2.pl 15 update.bat 1 xcopy_sp.sh 18791 total
When an option is specified, wc only reports the information requested by that option. Option -w counts words. Historically, the wc defines a word as a ``maximal string of characters delimited by <space>, <tab> or <newline> characters''. Such a definition creates problem with non-printable characters. Most modern implementations defines a ``word'' in terms of the isspace(3) function, as required by IEEE Std1003.2-1992 (``POSIX.2'').
The default behavior presuppose options -clw having been specified.
If no option is specified, the default is -lwc (counts lines, words, and bytes.). The -c and -m options are mutually exclusive.
who | wc -l
counts the number of users logged
ps -e | wc -l
counts the number of processes
ls -l | grep ^d | wc -l # finds the number of subdirectories in the current directory.
wc -l /etc/passwd
tells you the number of lines (accounts) in the /etc/passwd file.
wc -w readme.txt
counts the number of words in the file named readme.txt
Useless Use of wc -lThis is my personal favorite. There is actually a whole class of "Useless Use of (something) | grep (something) | (something)" problems but this one usually manifests itself in scripts riddled by useless backticks and pretzel logic.
Anything that looks likecan usually be rewritten like something along the lines ofsomething | grep '..*' | wc -lor even (if all we want to do is check whether something produced any non-empty output lines)something | grep -c . # Notice that . is better than '..*'(or grep -q if your grep has that).something | grep . >/dev/null && ...
If something is reasonably coded, it might even already be setting its exit code to tell you whether it succeeded in doing what you asked it to do; in that case, all you have to check is the exit code:something && ...
I used to have a really wretched example of clueless code (which I had written up completely on my own, to protect the innocent) which I've moved to a separate page and annotated a little bit. It expands on the above and also has a bit about useless use of backticks (q.v.)
wc- display a count of lines, words and characters in a file
wc [-c| -m| -C] [-lw] [file...]
The wc utility reads one or more input files and, by default, writes the number of newline characters, words and bytes contained in each input file to the standard output.
The utility also writes a total count for all named files, if more than one input file is specified.
The following options are supported:
Same as -m.
Count words delimited by white space characters or new line characters. Delimiting characters are Extended Unix Code (EUC) characters from any code set defined by iswspace().
If no option is specified the default is -lwc (count lines, words, and bytes.)
The following operand is supported:
A path name of an input file. If no file operands are specified, the standard input will be used.
See largefile(5) for the description of the behavior of wc when encountering files greater than or equal to 2 Gbyte ( 231 bytes).
See environ(5) for descriptions of the following environment variables that affect the execution of wc: LC_CTYPE, LC_MESSAGES, and NLSPATH.
The following exit values are returned:
An error occurred.
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
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: September, 12, 2017