Comment # 5 on bug 92164 from Simon McVittie

(In reply to Patrick Ohly from comment #4)
> I'm going to use this instead

Did this happen?

> if which dbus-send >/dev/null 2>&1; then

You might want

    if command -v dbus-send >/dev/null; then

which I believe is guaranteed to work by POSIX.1-2008 (and usually a shell
builtin in practice), whereas which(1) is commonly available but not part of
any standard that I know of.