How do I open deja-dup during a current backup?

Solution 1:

first install xdotool if you didn't do yet.

sudo apt-get install xdotool

Now specify the PID of the deja-dup backup process.

ps aux | grep deja
user  32052 18.5  0.1 1166992 33240 ?       Sl   13:31   0:00 gnome-control-center deja-dup
user  32073 11.5  0.0 744364 19704 ?        SNl  13:31   0:00 deja-dup --backup
user  32100  0.0  0.0   9452   944 pts/2    S+   13:31   0:00 grep --color=auto deja

save the PID of the --backup process which is 32073 for this example

Now use the xdotool

xdotool windowactivate `xdotool search --pid PROCESS_PID | tail -1`

In this example means

xdotool windowactivate `xdotool search --pid 32073 | tail -1`

and this will bring back the deja-dup backup window so you can do what you want.