User-Agent:       Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36
(KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36
Build Identifier: 

/etc/init.d/vboxadd status
/etc/init.d/vboxadd: line 118: .: filename argument required

It appears that

"if test -r $config; then"

does not do the job.

"if [[ -r $config ]]; then"

works for me, meaning it doesn't throw an error because it can't source a
missing file.

---

The package in question is: 

virtualbox-guest-tools-5.1.22-19.18.1.x86_64


Reproducible: Always