Is a file still use by php process

Question

I have a 3.2G file in /tmp called phpvXcoZn and I need to remove it. Therefore I'd like to know if it is still in use but the commands I typed returned nothing :

/tmp$ bigfile=phpvXcoZn
/tmp$ ll -h $bigfile
-rw------- 1 www-data www-data 3.2G Aug 25 09:49 phpvXcoZn
/tmp$ cd
$ sudo lsof | grep $bigfile
$ sudo fuser -avm /tmp 2>&1 | grep $bigfile
$ sudo ls -l /proc/*/fd/* 2>/dev/null | grep $bigfile
$ 

EDIT0: As @MarcusMüller suggested, I can try to unlink the file and the space usage will we freed when the file is closed but I cannot unlink that file belonging to www-data with sudo su :

$ sudo su www-data -c "unlink /tmp/phpvXcoZn"
This account is currently not available.
$ grep www-data /etc/passwd
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin

This command worked : sudo -u www-data bash -c "unlink /tmp/phpvXcoZn"

Do you other command to know if it is still in use ?

Answer 1

rming a file that is still open somewhere else has no effect on the program that has it still opened. It just can't be opened through the file name anymore – and as soon as it is closed, its storage can be freed. See man 2 unlink.