Linked by Thom Holwerda on Tue 27th May 2008 13:08 UTC, submitted by Ward D
AWK is one of the most common UNIX tools to process text-based data in either files or datastreams. Written by Alfred Aho, Peter Weinberger, and Brian Kernighan, AWK "extensively uses the string datatype, associative arrays (that is, arrays indexed by key strings), and regular expressions." ComputerWorld interviewed Alfred Aho.
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RE[2]: what an wonderful tool
by whartung on Tue 27th May 2008 22:11
in reply to "RE: what an wonderful tool"
Member since:2005-07-06
There are other great tools, little tools that simply do their job, just to mention a few: sed, grep, cut.
AWK makes me hate cut.
Why oh why oh why can't cut compress white space just like AWK does. By default, AWK separates fields based on one or more white space.
1 2 <-- There's supposed to be several spaces here, but HTML eats them
is the same as
1 2
AWK treats the spanning white space as a single delimiter.
But oh no, not cut. Nope. If you use " " as a delimiter in cut, you'll get a field for every single space.
*sigh*
Even today, modern cut can't do that -- even as an option. So, I use AWK.
Just a pet nit...
Edited 2008-05-27 22:15 UTC
RE[3]: what an wonderful tool
by malkia on Wed 28th May 2008 00:23
in reply to "RE[2]: what an wonderful tool"
Member since:2005-07-17
First, thanks for the nice AWK tips there. I should learn more AWK.
I'm still using only cut, sed, tr, etc.... I'm working mostly on Windows (which I do not like much) but that's my job - so cygwin on the help.
As for your example for cut and white spaces, here is how it can be solved:
cut --help | sed -r "s/[ ]+/ /g" | cut "-d " -f 2-
I guess sed can be used to replace two or more spaces to one, and then preprocess...
RE[3]: what an wonderful tool
by news7os on Wed 28th May 2008 13:13
in reply to "RE[2]: what an wonderful tool"
Member since:2008-05-28
RE[3]: what an wonderful tool
by Doc Pain on Thu 29th May 2008 20:43
in reply to "RE[2]: what an wonderful tool"
Member since:2006-10-08
AWK makes me hate cut.
As you pointed out correctly, there are cases when cut isn't the best tool. But that's tht nature of a tool - use it for what's it good at, and don't use it when it creates more problems than simply using another tool.
Cases where cut is a good tool are, where
1. you just want one of n fields,
2. the field delimiter isn't a space or a tab and
3. when you don't need to care for multiple spaces or tabs.
I remember a case where all three cases were met: I needed a stupid script that would extract all the nicknames from my X-Chat log files, so I did - and don't try this at home, kids - the following stupidity:
cat ${LOGFILES} | grep "<" | grep ">" | grep -v "CTCP" | cut -d '<' -f 2 | cut -d '>' -f 1 | sort | uniq -d | xargs echo > nicklist.txt
After I entered it and saw that it worked, I thought that I'd have better used awk... :-)
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Member since:
2006-10-08
Oh how I love these articles. =^_^=
I can only agree to that. Even today - why "even"? - awk is one of the tools I use. For example, I just wrote a simple awk script to convert a csv (comma seperated values) list file into a HTML and a LaTeX fragment. No big deal. Why? First of all, awk comes with my OS, I don't need to install anything (I'm using FreeBSD), no fat dependencies, and a great man page. And if you are familiar with C and know how to formulate regular expressions (as you need them), awk is a fast helper.
There are other great tools, little tools that simply do their job, just to mention a few: sed, grep, cut.
Yes! :-)
Match? Fire! Next.
By "match" you can attach actions to regex patterns of other conditions (e. g. line counters).
!/^#/ && (length != 0 || dings > 50) {
_____gsub($1 $2 bla bla bla);
_____pups = sprintf("zeux %dies %das %jenes", uhu, kram);
_____printf("bla", pups, furz);
_____dings++;
}
# And now for something completely different.