Testing functions and position arguments.

First is simply that the original positional arguments are preserved.

  $ cat > test.sh << EOF
  > echo "\$1 from \$0"
  > EOF

  $ sh test.sh hello
  hello from test.sh
  $ msh test.sh hello
  hello from test.sh

Next, do they work inside function definitions!

  $ cat > test.sh << EOF
  > shout () {
  >   echo \$0
  >   echo \$1 | tr a-z A-Z
  > }
  > shout "hi there"
  > EOF

  $ sh test.sh
  test.sh
  HI THERE
  $ msh test.sh
  test.sh
  HI THERE

Redirection and exit codes should be preserved to just like any other command.

  $ cat > test.sh << EOF
  > goodbye () {
  >   echo "eybdoog"
  >   exit \$1
  > }
  > goodbye 0 | rev
  > goodbye 1 | rev
  > goodbye 128
  > EOF

  $ sh test.sh
  goodbye
  goodbye
  eybdoog
  [128]

  $ msh test.sh
  goodbye
  goodbye
  eybdoog
  [128]