PHP: Remove invalid characters from file names

Characters such as "?", "\", "/", "*" or "|" are not allowed in file names on Windows and other operating systems. Therefore, we need to remove these characters from a string if we want to use it as a file name.

With this line of code, you can simply delete those characters from an arbitrary string with the help of PHP:

$f = 'fi?le.txt';

$f = str_replace(array('\\','/',':','*','?','"','<','>','|'),' ',$f);

echo $f; // 'fi le.txt'

The respective characters are simply replaced by a space here.

Alternatively, you can also just use another character instead of the space or write '' to the replace function in order to delete the characters completely without any substitute.