The Code is the Design

From terminal: cat Duplicates.txt | sort | uniq -c > Counts.txt Within vi: :%sort         // sort the results as required by "uniq" :%!uniq -c   // use the *nix "uniq" tool to prepend counts :%sort!        // sort in reverse order

Linux sendmail sometimes drops emails mysteriously without any error message or log of the written email. /var/log/maillog will show an entries such as: Unauthenticated email from xyz.com is not accepted due to [DMARC] The way to fix this is to have the domain name of the current server in the from field, and the actual from address in the reply-to field. This can easily be done with Drupal 7 using the contact_reply_to module. Drupal 8 does not require the module.

Module pages usually say: "The most complete and up to date documentation is included with the module, in the README.txt file." But the online README.txt files linked to there usually include documentation for unreleased updates. This can cause considerable confusion / unnecessary trouble-shooting when newly installing modules. Always use the README files included with the module, not the ones online.

// The following code will ensure that there are no more than 30 non-cached requests in 60 seconds. // Please adjust the first two variables below in a manner optimal to your server config. // Note that this only protects heavier non cached pages. // A powerful enough attack can even overload your server with requests for cached pages. function hook_init() {     $MinTime = 60;     $MaxAttmpts = 30;     $MyAppDDoSCheckUrl = variable_get('MyAppDDoSCheckUrl');     $TimeCheckNow = time();     if ($MyAppDDoSCheckUrl == '')     {         variable_set('MyAppDDoSCheckUrl',$TimeCheckNow.',1');         return;     }     $SerDDosVars = explode(',',$MyAppDDoSCheckUrl);     $TimeLast = intval($SerDDosVars[0]);     $ReqAttmt = intval($SerDDosVars[1]);        ...

Here's the code for iterating through all fields in a form and setting $element [ '#input_group' ] = TRUE ;     function hook_form_alter ( & $form , $form_state , $form_id ) { if ( $form_id == 'nodetype1_node_form' ) { iterateForm ( $form , 'setIgt' ) ; } } // Generic iterate function. Can be used with any callback. function iterateForm ( & $form , callable $callback ) { foreach ( element_children ( $form ) as $key ) { $element = & $form [ $key ] ; $children = element_children ( $element ) ; if ( empty ( $children ) ) { call_user_func_array ( $callback , array ( & $element , & $key ) ) ; } else { iterateForm ( $element , $callback ) ; } } } // Custom callback function setIgt ( & $element , & $key ) { if ( $element [ '#type' ] == 'textfield' ) $element [ '#input_group' ] = TRUE ; }

<?php for ($i = 1; $i < 1000; $i++) {     $print = TRUE;        // Optimized till square roots     for ($j = 2; ($j*$j) <= $i; $j++)     {         $print = FALSE;         if ($i % $j == 0)             break;                $print = TRUE;     }     if ($print)         print $i.','; } ?> <? // Here's a little trick I learnt from a friend almost 30 years ago // Counting Prime numbers $StartTime = time(); $PrimeCount=0; for ($i=1; $i<200000; $i++) { $IsPrime = true; for ($j=2; ($j*$j)<=$i; $j++) { if (($i % $j) == 0) $IsPrime=false; } if ($IsPrime) $PrimeCount++; } $TimeTaken = (time() - $StartTime); echo 'Counted '.$PrimeCount.' prime numbers in '.$TimeTaken.' seconds.'.PHP_EOL; // Ga...

Computers are basically for the automation of repetitive work. So programming computers is essentially the art of automation of repetitive work using loops. Thus, the most essential thing one needs to understand to program computers is how to write loops. That covers everything essential. PS: Recursion is assumed here to just be a more advanced form of a loop, which is just a more elegant solution for certain types of problems.