is there a better way to search for shell-script commands in google

Many times , i was stuck in shell script commands and couln’t even find it on google, when i directly type them in the search.Is there any way to search for , or any other reference site where i can get most information on the commands.
could you please explain what these does.

1) -inv ${SITE}

2) ${first}/* ${second}

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Author: nikhil2000