Aliases are handy shortcuts you can use when communicating with text pilots. They consist of a dot command, which is a period followed by any number of characters without whitespace (as in .txv), followed by up to 9 optional parameters (such as .txv 27 b). Entering the above command will send the pilot the message "runway 27, taxi via B; wind (wind), altimeter (altimeter)". You can see how this could save some time and hassle.
Aliases are defined in the alias file, which you should have downloaded from the controller downloads page and imported in VRC. The file consists of text only and is easy to read once you are familiar with the alias variables and functions published here. Below you can find a short list of aliases relevant to the ground control position. This list is not exhaustive, so consult the alias file itself if you want to learn more.
"pushback and start-up at pilot's discretion; advise when ready to taxi"
.txv (runway) (taxi route)
Use this for runway taxi instructions. Type ".txv 24l d8 e v" for "runway 24L, taxi via D8 E V. Wind (wind), altimeter (altimeter).".
[email protected] (runway) (intersection) (taxi route)
Use this for intersection departures. Type "[email protected] 25r f c10 b" for "runway 25R at F, taxi via C10 B. Wind etc..."
.txgv (taxi route) and .txpv (taxi route)
Use these for "taxi to gate via" and "taxi to parking via".
Hold short. Self-explanatory.
Cross runway. Self-explanatory. Note that current procedures require runway crossing instructions to specify the taxiway at which the runway should be crossed. This is not included in the alias, so you'll have to type it out yourself until the alias is revised.
.ho (tower controller ID)
"Contact [controller] on [frequency]". The controller ID can be found next to the controller's name in the controller list.
.bound (departure sector ID) (runway) (scratchpad code)
Ground controllers are required to send a boundary notification when an overlying radar controller is online but tower is not. This is the quick and easy way to do it. First, the aircraft in question must be selected! Then simply type something like ".bound 1a 27 zo" and the departure controller (SCT_APP in this case) will get a nifty private message saying "[callsign] 27 zo", thus fulfilling the boundary requirement. Instead of the scratchpad code, you can of course use "270 vectors PGY" or whatever makes sense for when the pilot is expecting radar vectors.