exec - execute commands in the operating system shell

    exec [options] -- [command]

Execute a command in the operating system shell.  All supplied arguments are
concatenated and passed as a command to popen(3).  Whitespace is not guaranteed
to be preserved, even if quoted.  stdin and stderr are not connected, while stdout is
logged unless the "-q" option is specified.


    -q
        Suppress stdout and stderr from subprocess

    -expect-return <int>
        Generate an error if popen() does not return specified value.
        May only be specified once; the final specified value is controlling
        if specified multiple times.

    -expect-stdout <regex>
        Generate an error if the specified regex does not match any line
        in subprocess's stdout.  May be specified multiple times.

    -not-expect-stdout <regex>
        Generate an error if the specified regex matches any line
        in subprocess's stdout.  May be specified multiple times.


    Example: exec -q -expect-return 0 -- echo "bananapie" | grep "nana"