Useless Use of Argument as Argument

[codedot]

       ListShellHook
              This is like ListHook, but the whole argument is given to the shell as
              argument, and the input and output file are stdin and stdout.

              i.e.:
              ListShellHook: cat
              works but does nothing but useless use of a shell and cat, while
              ListShellHook: grep-dctrl -X -S apt -o -X -S dpkg || [ $? -eq 1 ]
              will limit the update rule to packages from the specified source pack‐
              ages.

- Manual page of reprepro(1)