A simple answer is:
echo " lol " | xargs
Xargs will do the trimming for you. It’s one command/program, no parameters, returns the trimmed string, easy as that!
Note: this doesn’t remove all internal spaces so
"foo bar" stays the same; it does NOT become
"foobar". However, multiple spaces will be condensed to single spaces, so
"foo bar" will become
"foo bar". In addition it doesn’t remove end of lines characters.