AwkChannelWiki: Home Page

This wiki is maintained by regulars from the #awk channel on irc.libera.chat (and previously irc.freenode.net).

What is awk? see What_is_awk

Feel free to edit the wiki, just press edit button, the formatting rules are summarized at the bottom of the edit box. If you are afraid to break something, feel free to play in the SandBox. If you feel you need more info see How to edit. You can download a full backup of the wiki there: http://awk.freeshell.org/download/

#awk

#awk is small with a low traffic, and is not different from the other channels of this size on irc ie:

Do not wait to see if someone is awake to ask your question, we will answer if we see one when we see it.
Be patient, we do answer to most of the questions
The best way to ask a question on #awk is often to use a PasteBin containing a sample of your input data and a sample of the output you expect.
if #awk doesn't answer maybe consider asking in comp.lang.awk

Here is an, incomplete, not always up to date, list of some of the ChannelRegulars

Documentation

the traditional Frequently Asked Questions and their answers
XMLScraping ok, you don't want to use a parser
All about getline, by Ed Morton (comp.lang.awk): AllAboutGetline
some AwkTips
AwkFeatureComparison -- handy matrix to know what you can or cannot do with your awk
BeforeAfterMatch -- if what you want depends on the content of other lines
GeneralizedTextReplacement -- what to do if you desperately need backreferences
elsewhere on the web
CookBook -- just started, please contribute
AwkGuide -- work in progress
MicrosoftWindowsInstallation -- Installation of an awk interpreter in Microsoft Windows

Useful code snippets

FindAllIndices of a particular character in a string
FindAllMatches of a particular pattern in a string
RepeatAString n times
FormatFileSizes in human readable format
LevenshteinEditDistance to compute a score for the difference of two text strings
PrimeNumberSieve implemented in two slightly different ways, with comparative performance numbers under a variety of implementations
ComparingTwoFiles an example
DeleteTrailingNewlines
Adler32Checksum in pure awk
Columnate a file
ContextGrep -- print context lines around a match
Shellquote strings for use in shell commands
Transpose a file
SimpleCalc simple 4 operations calculator....no particular use
ReadDirectory read list of files in a directory
ReverseMapping reverse the mapping of keys -> values in an array

gawk specific code snippets

The following functions utilize gawk specific features, and so require the use of the gawk interpreter in order to operate:

ConvertHexToFloatingPoint - turns a hex string of 4 bytes of IEE754 Floating point back into a floating point number
GeoLocation Find where your IP address is located

Requests for Implementation

It may be that some people in the channel want code written to solve specific problems. These solutions may benefit from review, cooperative work and a location perhaps a bit more permanent than a PasteBin.

Tasks that require AWK solutions on Rosetta Code
rawtaz's TCPDumpParser?, which was used to filter IPs during a DoS attack
Thanatermesis's LshalOutputParser, which was used to find all the storage devices listed by the lshal utility
ajai / mib's FileAndBitJoinClone, which was used to print out the lines from an input file called bit.txt that were referred to in a file called file.txt (unfortunately this is as specific a description of these two files as was ever provided; it is all very abstract)
Recursively Include C headers
Eric S Raymond's https://gitlab.com/esr/tapview consumer for the Test Anything Protocol https://testanything.org/ is written in Bash for portability's sake, but should instead be ported to Awk for performance's sake.

Variants of awk

Thank you!!

The StyleSheet of this wiki has been borrowed (with permission) from the heirloom project website.

Be sure to check this excellent project, it provides, among many many other utilities, 2 implementations of awk: oawk and nawk

HomePage