using PARALLEL as variable name is a bad choice

[leapfog]

from man parallel:

The environment variable $PARALLEL will be used as default options for GNU parallel.

Using a variable with that name in your script breaks both, GNU Parallel and your script
(in case that variable was already defined and exported in the shell running prsync):

• the default options aren't used anymore (as you replaced them with a number)
• GNU Parallel inserts it between the options you specify and the rsync command

see:

$ export PARALLEL="foobar"
$ prsync --dry-run /etc /tmp
[...]
4 rsync --files-from=/tmp/tmp.x5RPF2DlGl/chunk.0 --dry-run /etc /tmp

(note the 4 before rsync)

[nathanhaigh]

Thanks for reporting this issue so clearly @leapfog! Now fixed.