Abnormal command termination

[tknight00]

I'm running your lib on
Linux 4.14.98 aarch64

I'm getting this on, what I assume to be, every listener interval
2020-10-14 16:09:48.483 WARN 2774 --- [ Thread-11] n.s.u.process.CommandExecutor : Abnormal command 'df -l' terminantion. Exit value: 1

This is the DF usage as printed by the OS. As you can see, there is no -l switch available.
Usage: df [-PkmhT] [FILESYSTEM]...

[tknight00]

Additionally there appears to be no difference in output between "df" and "df -l" when tested on a modern Ubuntu build and the older build without the "-l" flag.

The older board in question:
df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 14396516 870736 12894356 6% /

Ubuntu 18
df
Filesystem 1K-blocks Used Available Use% Mounted on
udev 993292 0 993292 0% /dev

Ubuntu 18
df -l
Filesystem 1K-blocks Used Available Use% Mounted on
udev 993292 0 993292 0% /dev

Can you drop the "-l" flag?