Shell – Xargs and rm with a *

Use -I {}, and {} at the place where you want the argument to appear:

xargs -I {} -n 1 echo rm /usr/src/packages/{}

(You can use something other than {}, {} is just very common.)

Without this, xargs simpy adds the input as additional arguments, so it's not a question of it adding spaces anywhere - the command receives the input as separate arguments.

You probably should use find instead of ls, especially if you want to distinguish files and directories.

Something like this to delete only files:

find . -type f -exec rm /usr/src/packages/{} \;