If we try to use the user module without being root, it fail on RHEL/Fedora
because usermod --help cannot be run. The root cause is lack of permission
due to EAL4+ certification, as seen in shadow-utils changelo.
So if we cannot run it, assume there is no append. It doesn't matter
much since we will not be able to run usermod at all with or without the
option.
If no group was specified, but a group by the same name as the user
exists, an error was raised in the situation where USERGROUPS_ENAB is
enabled in /etc/login.defs (which is the case for almost every major
linux distro). In this case, the user will be put in group 100 (which
is usually the "users" group on those same distros). This is currently
only done in the base class, as the issue may not exist on other
platforms like AIX or the BSDs.
Fixes#6210
Migrated all examples: in DOCUMENTATION=''' string to standalone EXAMPLES=''' string
Added deprecation warning to moduledev.rst and remove deprecated example from it
Fixed up a few typos and uppercased some acronyms.
add consistency to how EXAMPLES are formatted
Also consolidated duplicate groups code into one get_groups_set() method.
Removed unused call to user_group_membership.
Removed sorting operations on set functions cause sets are inherently unordered.
Minor style improvements to match the rest of the code.
The new function will make the order of group names passed to the system command less determistic.
Which was already the case for modify_user_usermod() but not for other methods.
It will also strip out duplicate group names automatically which was not always the case previously.