You can start DelOld from the cmd line using just
C:\> delold
however it has much more powerful command line options which can be seen using the /? or -? switch.
Setting the switches sets the relevant items on the GUI.
If you type a path without any files then it just sets the initial location, if you enter a file spec at the end of the path it will also set the file type to check for (you can set multiple file types by entering a comma between them but DON'T add a space, e.g. delold d:\temp\*.tmp,*.exe is fine).
The /q is quiet mode and when used with /-c (to turn off confirmation) then no GUI will be displayed and the operation will take place with no user intervention. If you do not use the /q switch then all other options can be set and you then need to press the 'Delete!' key to start the process.
You can add '-' to any switch to disable it. This is most useful for /c which is set by default.
You could schedule checks with the Windows NT scheduler when using the /q and /-c switches to automatically delete old files at specified times. An example submission would be
F:\> at 20:00 cmd /c delold /l /q /-c /n:90 /s /d d:\temp\*.tmp
The above would run the program at 8:00 p.m. with no user input (the /q and /-c) for any *.tmp file over 90 days old (/n:90) under d:\temp and all its subdirectories (/s). It would also delete any empty directories (/d) older than 90 days.
If you want to use from the command line without having to enter the path of delold.exe every time you can modify NT's path variable to included the DelOld program location.