PATH FUNCTIONS IN PHP

Following are the commonly php functions to get the path information of a file

Source php.net

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

Usage :
$realpath = realpath('./../../etc/passwd');
echo($realpath);

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pathinfo ( string $path [, int $options = PATHINFO_DIRNAME | PATHINFO_BASENAME | PATHINFO_EXTENSION | PATHINFO_FILENAME ] )
pathinfo() returns information about path: either an associative array or a string, depending on options.

Usage :
$path_parts = pathinfo('/www/htdocs/inc/lib.inc.php');
print_r($path_parts);

the extension of the file will be in $path_parts['extension']

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dirname ( string $path )
dirname — Returns parent directory's path. Given a string containing the path of a file or directory, this function will return the parent directory's path.

Usage:
$parent_dir= dirname("/etc/passwd");
echo($parent_dir);

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basename ( string $path [, string $suffix ] )
basename — Returns trailing name component of path. Given a string containing the path to a file or directory, this function will return the trailing name component. If the name component ends in suffix this will also be cut off.

Usage:
echo( basename("/etc/sample.d", ".d") ); // returns sample
echo(basename("/etc/")); // returns etc
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PHP Filesystem Functions