The command to run inside the container is `/etc`. The semicolon is a
statement terminator, which ends the command `docker run busybox /etc`,
while `echo $?` prints the exit code of that full docker command.
Having this mistake could confuse someone who thinks that `/etc; echo
$?` is all run inside the container, which wouldn't help the reader
understand the exit code of the `docker run` command itself.
Signed-off-by: Noah Silas <noah@hustle.com>
0c999fe95b