/recurse:[dir\]file
You can use wildcards in a file name to compile all matching files in the project directory without using /recurse. If no output file name is specified, the compiler will base the output file name on the first input file processed. This will generally be first file in the list of files compiled when viewed alphabetically. For this reason, it is best to specify an output file by using the /out option.
Compiles all VB files in the current directory:
vbc *.vb
Compiles all of the Visual Basic files in the Microsoft\WFC directory and any directories below it and generates Microsoft.WFC.dll:
vbc /target:library /out:Microsoft.WFC.dll /recurse:Microsoft\WFC\*.vb