Available regedit command switches and syntax that can be used.

REGEDIT [/L:system] [/R:user] [/C] [/R] [/E] [/S] [/C] filename [Registry_key]

/S	The /s or -s regedit commands can be added to the command to suppress the confirmation box "Are you sure want to add the information in hope.reg to the registry?" when running the command at the command line. For example, using the same command used earlier you can type: regedit /s hope.reg and have that registry file immediately imported into the registry.
/E	Export the full registry to a file. For example, typing: regedit /e full.reg would export the full registry to the full.reg file. This switch can also be used to export individual registry keys. For example, typing: regedit /e software.reg "HKEY_LOCAL_MACHINE\Software" would export all the the values in this folder to the software.reg file. Note: This is not case sensitive.
/D	Microsoft Windows 95, 98, and ME users can delete registry keys using this switch. For example, typing: regedit /d "<registry_key>" where registry_key is replaced with the registry key you wish to delete would delete that registry key.
/L:System	Specify the location of the system.dat registry file under Microsoft Windows 95, 98, and ME. For example, regedit /L:c:\windows\system.dat c:\system.dat
/R:user	Specify the location of the user.dat registry file under Microsoft Windows 95, 98, and ME. For example, regedit /L:c:\windows\system.dat c:\system.dat
/C	Compress registry file. This switch only works in Windows 98.