Ordinarily you don't need to give any arguments when starting Gimp, but here is a list of some that may at one time or anther be useful. This is not a complete list; on Unix systems you can get a complete list by running "man gimp" in a terminal window.
Display a list of all commandline options.
Print the version of Gimp being used, and exit.
Show detailed startup messages.
Do not load patterns, gradients, palettes, or brushes. Often useful in non-interactive situations where startup time is to be minimized.
Use the designated X display (does not apply to Gimp on Microsoft Windows).
Do not show the splash screen while starting.
Use a different sessionrc for this GIMP session. The given session name is appended to the default sessionrc filename.
Use an alternative gimprc instead of the default one. The "gimprc" file contains a record of your preferences. Useful in cases where plugins paths or machine specs may be different.
Do not popup dialog boxes on errors or warnings. Print the messages on the console instead.
Execute the set of commands> non-interactively. The set of commands is typically in the form of a script that can be executed by one of the GIMP scripting extensions. When commands is "-", the commands are read from standard input.