gistfile1.txt

cmd () {
  CMD="$1"
  DOCKER_CMD="docker run --rm --volumes-from ${CONT_NAME} ubuntu:14.04 bash -c \"sub1\""
  eval `echo $DOCKER_CMD | sed "s/sub1/${CMD}/"`
}

cmd "ls -l"

# läuft!

gistfile2.txt

cmd () {
  CMD="$1"
  docker run --rm --volumes-from ${CONT_NAME} ubuntu:14.04 bash -c \"${CMD}\"
}

cmd "ls -l"

# läuft nicht:
# -l": -c: line 0: unexpected EOF while looking for matching `"'
# -l": -c: line 1: syntax error: unexpected end of file