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Dont bother to write a Perl program

I can - very easily - write a Perl program to process every line of an incoming data file - indeed, that's much of where Perl originated as the "Practical Extraction and Reporting Language"

Here's a short example that processes every line of a file and reports each line that includes the string PHP as the second field of our line (which in the example happens to be a person's top skill):

open (FH,"../../requests.xyz") or die;
while ($line = <FH>) {
 chop ($line);
 @F = split (/\s+/,$line) ;
 if ($F[1] eq "PHP") {
  print $line;
  print "\n";
 }
}


Quick and easy, for sure ... but not as short (nor as quick and easy) as it might be for someone who's written a lot of Perl - this one line does the same:

perl -pae '$F[1] eq "PHP" or $_ = ""' ../../requests.xyz

Perhaps this is so short as to be obscure? If you're working in an environment when you often have to filter out a file quickly, then it's an excellent approach. If you're doing a lot of shell scripting, then a few Perl one-liners like this can save you an awful lot of more complex looking awks and seds.

As Damien Conway (one of the Perl team) said when I heard him lecture: "We're giving you a lot of very powerful tools. Be careful how you use them".
(written 2008-10-10)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P210 - Perl - Topicalization and Special Variables
  [3449] Apache Internal Dummy Connection - what is it and what should I do with it? - (2011-09-19)
  [2972] Some more advanced Perl examples from a recent course - (2010-09-27)
  [2876] Different perl examples - some corners I rarely explore - (2010-07-18)
  [2833] Fresh Perl Teaching Examples - part 2 of 3 - (2010-06-27)
  [1922] Flurinci knows Raby Lae PHP and Jeve - (2008-12-04)
  [1860] Seven new intermediate Perl examples - (2008-10-30)
  [1728] A short Perl example - (2008-07-30)
  [1705] Environment variables in Perl / use Env - (2008-07-11)
  [1704] Finding operating system settings in Perl - (2008-07-10)
  [1508] How not to write Perl? - (2008-01-15)
  [1444] Using English can slow you right down! - (2007-11-25)
  [1289] Pure Perl - (2007-08-03)
  [1232] Bathtub example - (2007-06-14)
  [1221] Bathtubs and pecking birds - (2007-06-07)
  [1136] Buffering output - why it is done and issues raised in Tcl, Perl, Python and PHP - (2007-04-06)
  [969] Perl - $_ and @_ - (2006-12-07)
  [639] Progress bars and other dynamic reports - (2006-03-09)
  [493] Running a Perl script within a PHP page - (2005-11-12)


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Web Bloopers - good form design - avoiding pitfalls
Processing all files in a directory - Perl
Text formating for HTML, with PHP
Caen Hill and Olivers Castle
Dont bother to write a Perl program
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What a shock
Perl - Subs, Chop v Chomp, => v ,
Question Mark - Colon operator (Perl and PHP)
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