> I put a g after the two slashes to modify both quiet AND rhgb.
I think if you need the g (global) then you may have had multiple
instances of the rhgb pattern present as kernel args.
[...]
The g is a good Idea in case something is writing multiple rhgb args
into the bootloader config on the kernel arg line.
No, 'g' is even required just to get rid of a single "quiet" PLUS a
single "rhgb". Compare:
echo 'linux quiet rhgb foo' | sed -e 's/quiet\|rhgb//g'
linux foo
echo 'linux quiet rhgb foo' | sed -e 's/quiet\|rhgb//'
linux rhgb foo
Without 'g' the OR expression operates only on the *first*
match. Either 'quiet' or 'rhgb' but not both: only the first one
found.
Also compare with this:
echo 'linux quiet rhgb foo' | sed -e 's/quiet//' -e 's/rhgb//'
linux foo
PS: Perl is really overkill here.