system() - Execute External Programs
This section provides a tutorial example on how to the system() function to invoke an external program. The program's standard output, stdout, and input, stdin, are shared with the calling script. The last line of stdout is returned as the return value.
The third option to execute a program on the operating system from a PHP script
is to use the system() function:
$line = system(string $command[, int &$rc]]);
- The first argument, $command, specifies the command line that invokes the external program.
- The second optional argument, $rc, specifies a string to store
the return code of the program.
- The return value is a string of the last line of the stdout.
- The standard input of the program, stdin, is shared with the calling script.
- The standard output of the program, $output, is shared with the calling script.
But the stdout stream buffer is flushed per each output line.
This is perfect for Web server to display output partial output as quickly as possible.
- The standard error of the program, stderr, is shared with the calling script.
Here are some examples of using the system() function:
herong$ php -a
php > echo system("whoami");
php > system("cat", $rc);
php > echo $rc; ;
Table of Contents
About This Book
Introduction and Installation of PHP 7.3
PHP Script File Syntax
PHP Data Types and Data Literals
Variables, References, and Constants
Expressions, Operations and Type Conversions
Conditional Statements - "if" and "switch"
Loop Statements - "while", "for", and "do ... while"
Function Declaration, Arguments, and Return Values
Arrays - Ordered Maps
►Interface with Operating System
$argv - Command Line Arguments
Options to Execute External Programs
`command` - Backtick Operator
exec() - Execute External Programs
►system() - Execute External Programs
passthru() - Execute External Programs
popen() - Execute External Programs
proc_open() - Execute External Programs
memory_get_usage() - Memory Usage Info
Introduction of Class and Object
Integrating PHP with Apache Web Server
Retrieving Information from HTTP Requests
Creating and Managing Sessions in PHP Scripts
Sending and Receiving Cookies in PHP Scripts
Controlling HTTP Response Header Lines in PHP Scripts
Managing File Upload
MySQL Server Connection and Access Functions
Functions to Manage Directories, Files and Images
SOAP Extension Function and Calling Web Services
SOAP Server Functions and Examples
Localization Overview of Web Applications
Using Non-ASCII Characters in HTML Documents
Using Non-ASCII Characters as PHP Script String Literals
Receiving Non-ASCII Characters from Input Forms
"mbstring" Extension and Non-ASCII Encoding Management
Managing Non-ASCII Character Strings with MySQL Servers
Parsing and Managing HTML Documents
Configuring and Sending out Emails
Image and Picture Processing
Managing ZIP Archive Files
Managing PHP Engine and Modules on macOS
Managing PHP Engine and Modules on CentOS
Full Version in PDF/EPUB