In Ubuntu (21.10), I start a file manager from the command line window (gnome terminal 3.38.1):
nemo .
Sometimes, the command line returns and I can enter more commands. Sometimes, the command line is blocked by the running process until I close the file manager window.
I know that I can launch the process in the background (by appending "&"). But what I do not understand are the conditions that cause this behavior to differ between sessions. What is the cause?
Many graphical applications, apparently including nemo, work this way:
A user can only run one instance of the said application at a time. If multiple windows are open, it's still a single process that takes care of all of them.
If the application is not yet running then the currently executed nemo command will be that application. Therefore, you get back the prompt only when it quits (i.e. you close all its windows).
However, if the application is already running then the new nemo command just sends a message to the already running instance, instructing it to open a new window, or to bring the existing windows to the front, or alike. In this case the newly executed nemo command returns immediately.
