It is also possible to start 4TeX with the Main file and Current file, e.g.
will start 4TeX with the main file C:\TEXFILES\BOOK.TEX
4TEX.EXE C:\TEXFILES\BOOK.TEX C:\TEXFILES\CHAP1.TEX
will start 4TeX with the Main file C:\TEXFILES\BOOK.TEX and the Current file C:\TEXFILES\CHAP1.TEX
Some people prefer different/multiple 4TEX.INI files for different tasks. You can have, e.g., the INI files 4TEX.MED and 4TEX.WINEDT that are copies of the 4TEX.INI file and then changed to suit the needs for the MED editor and the WinEdt editor. If you want to start 4TeX with a different INI file just type (or better yet, make a shortcut):
4TEX.EXE -INIFILE 4TEX.MED
4TEX.EXE -INIFILE 4TEX.WEDT
The INI files 4TEX.MED and 4TEX.WINEDT should be stored in either the Windows directory or in the same directory as 4TEX.EXE.