vsim -help gives the various allowed options.
vsim -view vsim.wlf allows us to view the contents of the wlf file.
But I wanted to know the usage of & at the end of the command.
Hei that is not command dependent. it just instructs to run this process(Her your vsim command) as a background process. It is unix related. it will help to easily kill the window if it gets hanged.