Ubuntu – How to get to show the full name of application in ‘Show Applications’ and ‘Files

All utilities get their information from /proc/$PID anyway, but there are (at least) three places in /proc/$PID that contain the name of the executable in some form, and they report different information.

• The Name field in /proc/$PID/status (also available in a harder-to-parse form in /proc/$PID/stat). This is the name of the executable, but truncated to 15 characters. Since the kernel performs the truncation, no option to ps can help. That's what ps -o comm (or its synonym ps -o ucmd) shows.
• The symbolic link /proc/$PID/exename point to the executable file. You can get its contents with readlink /proc/$PID/exename. Unlike the information reported by ps, only the user running the process has permission to read the link target.
• The zeroth argument to the process, as chosen by the shell or other program that invoked it. By convention, shells choose the name of the executable as you typed it (with or without a full path). You can get all the arguments from ps with ps -o cmd (or its synonym ps -o command), but the arguments are separated by spaces so you can't reliably tell where the zeroth argument stops. You can read the arguments from /proc/cmdline, where they are separated by null character: </proc/$PID/cmdline awk -vRS='\0' '{print; exit;}' extracts the zeroth argument.

For completeness, let me mention that these names can change during the lifetime of the process, though most programs don't do it:

• The process can change Name field of /proc/$PID/status by calling prctl with the PR_SET_NAME argument.
• The executable file can be renamed or deleted. In simple cases, Linux keeps track of the new name (but edge cases might not work, e.g. if you make a hard link to the executable). If the file is deleted, the kernel adds (deleted) to the link target.
• The zeroth argument to the process is read from process memory (it's argv[0] in C). The process can modify it freely.

I played around with the gnome-shell.css (/usr/share/themes/[your-current-theme]), after I copied that folder to /home/user/.themes. In the gnome-shell.css is a section called Apps where you can change the grid size of the grid on which the icons are aligned - if you make that bigger (change contact grid entry accordingly) you will see more.

I also tried to find how the pop-ups, like on the overview sidebar, work - however I could not find that. Seems like that has nothing to do with CSS.