PHP: Is there a command that can delete the contents of a file without opening it?

Question

Is there any way to remove the contents of an file in php, do we have any php command that does that, I know unlink but I do not want to delete the file instead

Answer 1

You can't modify a file without opening it. The simplest way of doing that is to open it and truncate it while you open it, which in PHP would look like this:

fclose(fopen($filename, "w+"));

If you're going to invoke a unix shell (which is what the system() call does), the simplest way is to redirect /dev/null to the file, so in PHP that would be:

system(">$filename 

There's a lot more overhead to this approach but it can be generalized and translated to any language or environment where you have a shell. There are other answers on this thread that have you calling system() to rm and then touch to recreate the file - besides being non-atomic, that approach also scares me much more.