agreed, it's very unclear what you're wanting to do..2 things however,
tr is "translate charachters" not trim!
the format you're using is not correct, you don't have double quotes formatted correctly."actually you don't have double-quotes.
Code:
tr -s " "`" ## 3 quotes, not 4!
you also might want to use the ascii equiv to "`" char
or
tr -s " " "\`"
