On Tue, 2016-01-12 at 13:22 +0100, Florian Zieboll wrote:
> On Tue, 12 Jan 2016 08:48:45 -0300
> Renaud (Ron) OLGIATI <renaud@???> wrote:
>
> > Simple enough to change this into:
> >
> > user@devuan:~$ echo "xfce4-session" >> ~/.xinitrc  
>
>
> Yes – if there's no "exit" command contained in the existing .xinitrc.

What about: (saves a copy of the old file):

if [ -f test ]; then
    mv test test.old
    echo "new_entry" > test
else
    echo "new_entry" > test
fi

or:

if [ -f test ]; then
    mv test test.old
fi
    echo "new_entry" > test