PHP
Basics
Script language for dynamic web-pages. The syntax and concepts used are similar to Perl
Limited number of loops:
for ($i = 0; $i <= 6; $i++) {
echo "Loop number: $i ";
}
- escapeshellcmd(shellcommand)
- Return the shellcommand with everything that might confuse the shell escaped.
- exec(<cmd>,<outputarray>,<returnvar>)
- Executed <cmd> in the shell, append the command output to he array <outputarray> and set <returnvar> to the returnvalue of the command.
- Also the last line of the command output is returned
- shell_exec(<cmd>)
- Execute <cmd> (output from excapedshellcmd) in the shell, return the command output.
- date("Y-m-d h:i:s")
- Current timestamp (YYYY-mm-dd HH:MM:SS)
- sprintf("%7.2f",$float )
- Format a number (7 digits, 2 decemals)
- strpos($string, $search,$start)
- Return position of $search exists in $string. When it is not in, return FALSE. Start searching at position $start (optional). Simple test on strpos -
if (strpos(x,y)) {}
- does not differ between position 0 and FALSE. Test on position 2 or count from the end by setting $start to a negative value (possible since PHP7.1). - str_replace($old,$new,$string)
- Return $string with $old replaced by $new
Regular expressions
PHP is Perl-like, patterns need delimiters (default is /<pattern>/ )
- preg_match($pattern, $string)
- Return 1 if $pattern exists in $string
- preg_split('/\s*\=+\s*/',$string
- Split $string into an array on a pattern (in this example on white-spaces and equality signs.
- preg_replace('/#.*$/',,$string);
- Replace matches with the pattern in $string (in this example to remove comments from a line)
Files
Almost all you need to know about files. For writing open with 'w' and fwrite($fh,$line)
$fh = fopen($filename, 'r') or die('Unable to open '.$file);
while(!feof($fh)) {
$line = fgets($fh);
}
fclose($fh)
Functions
All variables are local to the function. You have to pass everything it needs.
<?php
function func1($arg1, $arg2)
{
<codeblock>
return $value;
}
?>
Arrays
- arr1 = ( val1, val2, val3 )
- Create an indexed array. The keys are the range 0..arraylength.
- $arr1 = array(key1=>val1, key2=>val2, key3=>val3)
- $arr2[key1] = val1
- Create an associative array (like a hash in perl)
- count(arr1)
- Return the number of elements (length) of an array
- foreach($arr1 as $value) { codeblock }
- Loop over an indexed array
- foreach($arr1 as $key => $value) { codeblock }
- Loop over an associative array
Install
On debian (and its derivates)
- apt-get install php-fpm php-mysql
- Install php7 and mysql support
- Fix php security by editing
/etc/php/7.0/fpm/php.ini
- Uncomment line with cgi.fix_pathinfo and set it to 0