php version

1echo PHP_VERSION;

1<?php
2echo 'PHP version: ' . phpversion();
3?>

1/* in terminal type it*/
2php -v

1<?php
2  echo 'PHP version:' . phpinfo();
3?>  

1PHP Versions
2	
3PHP/FI - (1995) 	
4Key Features - Form handling.
5Description - Perl/CGI script (PHP 1.0) introduced by Rasmus Lerdorf. The Expansion is Personal Home Page / Form Interpreter and the ability to work with HTML.
6
7PHP/FI2 - (1997) 	
8Key Features - Data conversion, 
9			   Form data export, 
10			   HTML Embedding.
11Description - With slight modifications in Form Interpreter(PHP 2.0) to handle form entries.
12
13PHP  3 – (1998) 	
14Key Features - PHP core is rewritten, 
15			   PHP parser is rewritten, 
16			   Zend Engine is incorporated.
17Description - Language core was changed by Zeev Suraski and Andi Gutmans and PHP refers to PHP: Hypertext Preprocessor.
18
19PHP 4 – (2000) 	
20Key Features - Object-Oriented support, 
21			   External resource handling, 
22			   Security, 
23			   RegEx handling,
24			   Enhanced run time execution,
25               Introduced Supergobals,
26			   Web server abstraction layer,
27               Object overloading support
28               Output buffering support,
29               Improved resource handling.
30Description - PHP version 4 powered by Zend Engine 1 was released for public usage. 
31  			  PHP 4 also comes with the web server abstraction that enables PHP to run on Microsoft’s IIS, Apache 2, Zeus and more. 
32			  By 2008, PHP version 4 had evolved and reached 4.4.9. However, PHP version 4 is no more supported for security updates.
33			  
34    		  1.PHP 4 uses “Compile first, execute later” paradigm whereas other previous versions employed the “execute while interpreting” paradigm
35              2.PHP 4 hosted multi-threading feature; you can run the lengthy but non-critical functions independently, which further streamlines execution.
36
37PHP 5 – (2004) 	
38Aimed Features - Improved object model, 
39			     PDO Support, 
40			     Exception handling, 
41			     XML support.
42                 
43Features of PHP 5. 1:
44->Support for custom auto loading.
45->Over 400 various bug fixes.
46->Significant performance improvements
47->Improved time zone support
48
49Features of PHP 5.2:
50->Improved memory manager
51->Increased default memory limit
52->New extensions with JSON, Zip
53->Input filtering extension
54->Upgraded bundle SQLite
55
56Features of PHP 5.3:
57->Support for namespaces
58->Support for jump labels
59->Dynamic access to static methods
60->Support for Late Static Bindings
61->A garbage collector for circular references
62
63Features of PHP 5.4:
64->Support for traits
65->Tracking the upload progress of files
66->Support for Binary number format
67->Function array dereferencing
68->Improved parse error messages
69
70Features of PHP 5.5:
71->empty() supports arbitrary expressions
72->Generators
73->password_hash()
74->Introduced finally keyword
75->array & string literal dereferencing
76
77Features of PHP 5.6:
78->Constant expressions
79->SSL/TLS improvements
80->Default character encoding
81->pgsql async support
82->Introduced phpdbg, an interactive debugger
83->Operator overloading
84->Gost-crypto hash algorithm
85
86Description - PHP core was almost stabilized with this release. 
87              Later 5.X releases have slight enhancement.
88 			  PHP version 5 scaled up to version 5.6. In December 2018, official support for PHP security ended but Debian continued to provide security support until 2020.
89
90PHP 6 - PHP version 6 was supposed to feature native Unicode support, but that extension never succeeded.
91        In the month of March 2010, the project php 6.0 in its current form was officially abandoned and PHP’s version 5.4 was released with non-Unicode features like traits and closure binding. 
92		This update left the developer community hoping for efficient Unicode integration.
93		So it was skipped and PHP 7 was released. You can get more information on this by going through the linked HN discussion.
94
95PHP 7 – (2016) 	
96Key Features - Improved performance (twice as that of 5.6), 
97			   Reduced memory usage,
98			   The null coalescing operator (??),
99    		   Return and Scalar Type Declarations,
100               Anonymous Classes,
101			   Zero cost asserts.
102                 
103Features of PHP 7.1:
104->Void functions
105->Nullable Types
106->Asynchronous Signal handling
107->Class Constant visibility
108->Symmetric Array Destructuring
109
110Features of PHP 7.2:
111->Abstract Method Overriding
112->New Object Type
113->Password hashing with Argon 2
114
115Features of PHP 7.3:
116->Trailing Comma
117->Flexible Heredoc and Nowdoc Syntaxes
118->PCRE2 Migration
119->JSON_THROW_ON_ERROR
120                 
121Features of PHP 7.4 (28 Nov 2019):
122->Typed Properties 2.0
123->Preloading
124->Null Coalescing Assignment Operator
125->Improve openssl_random_pseudo_bytes
126->Weak References
127->New custom object serialization mechanism
128->Password Hash Registry

1set PATH=%PATH%;C:\path\to\php
2