Okay so "-" isn't a systemd unit name. At this point, you might do well to examine dmesg. Check for fatals errors and warnings and see if any interesting material turns up.
On Tue, 5 Feb 2019, ghe wrote: > Date: Tue, 5 Feb 2019 13:17:49 > From: ghe <g...@slsware.net> > To: debian-user@lists.debian.org > Subject: Re: shell script problem > Resent-Date: Tue, 5 Feb 2019 18:18:34 +0000 (UTC) > Resent-From: debian-user@lists.debian.org > > On 2/5/19 9:19 AM, Jude DaShiell wrote: > > > Have you tried replacing "-" with \45 yet? That's the ascii equivalent > > for "-'. > > Excellent idea. But: > > root@sbox:~# systemctl unmask \45.mount > Unit 45.mount does not exist, proceeding anyway. > > (Same with quotes.) > > --