$ ls -l docs
ls: cannot access docs: No such file or directory
$ zkl
zkl: fcn createOutputTxt(dir){ dir=dir+"/docs"; File.mkdir(dir); File(dir+"/output.txt","w") }
Void
zkl: createOutputTxt(".")
File(./docs/output.txt)
zkl: createOutputTxt("/")
Stack trace for VM#1 ():
   Cmd.createOutputTxt@mkdir addr:16  args(1) reg(0)
   Cmd.__constructor@createOutputTxt addr:9  args(0) reg(0) R
   startup.__constructor addr:2271  args(0) reg(1) ER
   startup.__constructor addr:2207  args(0) reg(22)
Exception thrown: IOError(File.mkdir(//docs): Permission denied)
zkl: ^D
$ ls -l docs
total 0
-rw-r--r-- 1 craigd craigd 0 Oct 27 22:08 output.txt