What flag can be used with the ps command to show all processes more completely?

The flag used with the ps command to show all processes in a more complete manner is -e. This option instructs the ps command to list every process currently running on the system, regardless of the user who owns the process. When using -e, you get a broader view of processes, which is particularly useful for system monitoring and diagnostics.

In contrast, the -a flag is primarily used to show processes for all users but will not list processes that are not associated with a terminal. The -u flag allows you to display processes according to their user and includes additional information such as the user ID, but it does not necessarily show all processes. Lastly, the -x flag enables the display of processes that do not have a controlling terminal, but again it does not encompass all processes as -e does.

Thus, -e is the most comprehensive flag for showing all processes completely, facilitating better observation and management of system activities.