To specify argument/value pairs on the xe command line, write

argument=value

without quotes, as long as value doesn't have any spaces in it. There should be no whitespace in between the argument name, the equals sign (=), and the value.

For values containing spaces, write:

argument="value with spaces"

If you use the CLI while logged into a XenServer Host, commands have a tab completion feature similar to that in the standard Linux bash shell. If you type, for example

xe vm-l

and then press the TAB key, the rest of the command will be displayed when it is unambiguous. If more than one command begins with vm-l, hitting TAB a second time will list the possibilities. This is particularly useful when specifying object UUIDs in commands.