realpath函数的用法

realpath

(PHP 4, PHP 5)

realpath — Returns canonicalized absolute pathname

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 Description

string  realpath (  string $path )

realpath() expands all symbolic links and resolves references to '/./', '/../' and extra '/' characters in the input path and return the canonicalized absolute pathname.

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 Parameters

path

The path being checked.

Note:

Whilst a path must be supplied, the value can be blank or NULL In these cases, the value is interpreted as the current directory.

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Return Values

Returns the canonicalized absolute pathname on success. The resulting path will have no symbolic link, '/./' or '/../' components.

realpath() returns FALSE on failure, e.g. if the file does not exist.

Note:

The running script must have executable permissions on all directories in the hierarchy, otherwiserealpath() will return FALSE.

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 Changelog

Version	Description
5.3.0	Prior to this release, if only the last path component did not exist, realpath() would not fail on *BSD systems. realpath() now fails in this case.
5.0.0	Prior to this release, a blank or NULL path would cause realpath() to return the directory name of the script.

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 Examples

Example #1 realpath() example

chdir('/var/www/');
echo realpath('./../../etc/passwd');
?>

The above example will output:

/etc/passwd

Example #2 realpath() on Windows

On windows realpath() will change unix style paths to windows style.

echo realpath('/windows/system32');
?>

The above example will output:

C:\WINDOWS\System32