dbuck is broken on Linux

Created by: davido

running dbuck on Linux:

  uname -a
  Linux l4.1.34-33-default #1 SMP PREEMPT Thu Oct 20 08:03:29 UTC 2016 (fe18aba) x86_64 x86_64 x86_64 GNU/Linux

is failing for me with:

  $ dbuck build gerrit
  tail: cannot open ‘+2’ for reading: No such file or directory

when i replace tail +2 with tail -2 in this line, it's failing with different error:

  $ lsof -i:8888 | tail -2 | awk '{ print $2 }' | xargs -L1 kill -9
  kill: not enough arguments

It's also clear why: there is no such process. There is this xargs option

  -r, --no-run-if-empty
              If the standard input does not contain any nonblanks, do not run the command.  Normally, the command is run once even if there is no input.  This  option  is  a
              GNU extension.

so that the fix on Linux is:

  lsof -i:8888 | tail -2 | awk '{ print $2 }' | xargs -rL1 kill -9