On Fri, 22 Jan 2021 at 02:33, Stephen Morris <samorris@netspace.net.au> wrote:

Just on the topic of rkhunter, I've run the command rkhunter --check and
gotten a number of warnings. Among them were warnings about
/usr/bin/egrep, /usr/bin/fgrep, /usr/libexec/nm-ifdown and
/usr/libexec/nm-ifup having been replaced by a script and obviously not
whitelisted. Would the replacement of those commands be something done
within package management and rkhunter hasn't been updated to cater for
that, or am I encountering a situation where those commands have been
changed by something outside of the package management environment?


From "info grep":

  In addition, two variant programs ‘egrep’ and ‘fgrep’ are available.
‘egrep’ is the same as ‘grep -E’.  ‘fgrep’ is the same as ‘grep -F’.
Direct invocation as either ‘egrep’ or ‘fgrep’ is deprecated, but is
provided to allow historical applications that rely on them to run
unmodified.
Shorthand like "egrep" for "grep -E" were helpful when working at 300 baud.   
Years ago some UNIX systems used hard links.   Today, not all linux distros 
include egrep and fgrep.   Unless you need "historical applications that rely on 
them", just remove "egrep" and "fgrep" 

--
George N. White III