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Please ask about maintenance training for Perl, PHP, Lua, etc
 
Want to do a big batch edit? Nothing beats Perl!

Trainees in classI still love Perl ...

Wanting to convert a file of lines like this:
  <img src=rp_153_track.jpg><br><br>
into lines like this:
  rp_153_track.jpg <img src=rp_153_track.jpg><br><br>

The code is as simple as:
  /=(.*?)>/;
  print "$1 $_";


And it runs like this:
  perl -n pip images.html > labelledimages.html

See my results here




Wanting to copy all files in a subdirectory that were NOT present in any other subdirectory, and add in a "this is archived" header at the start of each of them:

opendir(DH,".");
@modules=grep(/[a-z]\d{3}/,readdir DH);
foreach $dir(@modules) {
  opendir(DH,$dir);
  next if ($dir eq "j610");
  while ($ent = readdir DH) {
    $found{$ent} .= "$dir ";
  }
}
opendir(DH,"X001");
@news = readdir(DH);
foreach $example(sort @news) {
  next if ($example =~ /^\./);
  if (! $found{$example}) {
    open (FH,"X001/$example");
    read (FH,$buffer,-s "X001/$example");
    close FH;
    open (FH,">j610/$example");
    print FH ("#%% $example\n");
    print FH ("--- ARCHIVED EXAMPLE (may not be current) ---\n");
    print FH ("--- See notes at http://www.wellho.net/mouth/2654.html ---\n\n");
    print FH ("$buffer\n");
    close FH;
    }
  }


Yes ... I know it's hard to follow, unstructured, unOO ... but it's PRACTICAL and Perl is nothing if not the practical extraction and reporting language!


Illustration - delegates on a Perl Training Course at our training centre.

(written 2010-03-01, updated 2010-06-23)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P212 - Perl - More on Character Strings
  [4452] Binary data handling - Python and Perl - (2015-03-09)
  [3927] First match or all matches? Perl Regular Expressions - (2012-11-19)
  [3707] Converting codons via Amino Acids to Proteins in Perl - (2012-04-25)
  [3650] Possessive Regular Expression Matching - Perl, Objective C and some other languages - (2012-03-12)
  [3630] Serialsing and unserialising data for storage and transfer in Perl - (2012-02-28)
  [3546] The difference between dot (a.k.a. full stop, period) and comma in Perl - (2011-12-09)
  [3411] Single and double quotes strings in Perl - what is the difference? - (2011-08-30)
  [3332] DNA to Amino Acid - a sample Perl script - (2011-06-24)
  [3322] How much has Perl (and other languages) changed? - (2011-06-10)
  [3100] Looking ahead and behind in Regular Expressions - double matching - (2010-12-23)
  [3059] Object Orientation in an hour and other Perl Lectures - (2010-11-18)
  [2993] Arrays v Lists - what is the difference, why use one or the other - (2010-10-10)
  [2877] Further more advanced Perl examples - (2010-07-19)
  [2874] Unpacking a Perl string into a list - (2010-07-16)
  [2834] Teaching examples in Perl - third and final part - (2010-06-27)
  [2801] Binary data handling with unpack in Perl - (2010-06-10)
  [2379] Making variables persistant, pretending a database is a variable and other Perl tricks - (2009-08-27)
  [2230] Running a piece of code is like drinking a pint of beer - (2009-06-11)
  [1947] Perl substitute - the e modifier - (2008-12-16)
  [1735] Finding words and work boundaries (MySQL, Perl, PHP) - (2008-08-03)
  [1727] Equality and looks like tests - Perl - (2008-07-29)
  [1510] Handling Binary data (.gif file example) in Perl - (2008-01-17)
  [1336] Ignore case in Regular Expression - (2007-09-08)
  [1305] Regular expressions made easy - building from components - (2007-08-16)
  [1251] Substitute operator / modifiers in Perl - (2007-06-28)
  [1230] Commenting a Perl Regular Expression - (2007-06-12)
  [1222] Perl, the substitute operator s - (2007-06-08)
  [943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
  [928] C++ and Perl - why did they do it THAT way? - (2006-11-16)
  [737] Coloured text in a terminal from Perl - (2006-05-29)
  [608] Don't expose your regular expressions - (2006-02-15)
  [597] Storing a regular expression in a perl variable - (2006-02-09)
  [586] Perl Regular Expressions - finding the position and length of the match - (2006-02-02)
  [583] Remember to process blank lines - (2006-01-31)
  [453] Commenting Perl regular expressions - (2005-09-30)

P222 - Perl - Programming Efficiency and Style
  [4611] Hungarian, Camel, Snake and Kebab - variable naming conventions - (2016-01-03)
  [2688] Security considerations in programming - what do we teach? - (2010-03-22)
  [2399] Firefighting with Perl - (2009-09-07)
  [1181] Good Programming practise - where to initialise variables - (2007-05-09)
  [743] How to debug a Perl program - (2006-06-04)

P772 - Practical Example - Perl in use
  [2129] Nothing beats Perl to solve a data manipulation requirement quickly - (2009-04-14)
  [2047] Small Web Server in Perl - (2009-02-18)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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