PHP
语言参考 | Language Reference

Execution Operators

Execution Operators

PHP supports one execution operator: backticks (). Note that these are not single-quotes! PHP will attempt to execute the contents of the backticks as a shell command; the output will be returned (i.e., it won't simply be dumped to output; it can be assigned to a variable). Use of the backtick operator is identical to shell_exec().

<?php $output = `ls -al`; echo "<pre>$output</pre>"; ?>

Note: The backtick operator is disabled when safe mode is enabled or shell_exec() is disabled. Note: Unlike some other languages, backticks have no special meaning within double-quoted strings.

See also the manual section on Program Execution functions, popen() proc_open(), and Using PHP from the commandline.

← Error Control Operators

Incrementing/Decrementing Operators →

© 1997–2017 The PHP Documentation Group

Licensed under the Creative Commons Attribution License v3.0 or later.

https://secure.php.net/manual/en/language.operators.execution.php