If you are cPanel user, you shall know that cPanel do allow addon some plugin named ClamAV and it is totally free to use for user.
Once you install the clamAV plugin, you shall be able to see Virus Scanner from your cPanel account, then you are allow to scan your file and folder if any file infected.
However, do you know that you could actually done it through SSH as well, by using clamscan command, you are able to scan your file.
$ clamscan index.php
———– SCAN SUMMARY ———–
Known viruses: 788386
Engine version: 0.95.3
Scanned directories: 0
Scanned files: 1
Infected files: 0
Data scanned: 0.01 MB
Data read: 0.01 MB (ratio 0.00:1)
Time: 3.312 sec (0 m 3 s)
else, you may perform clamscan * for wildcard.
$ clamscan *
Where it will scan all of your file.