def _sh_quote(s):
    """Return a shell-escaped version of the string `s`."""
    if not s:
        return b""
    if _find_unsafe(s) is None:
        return s

    # use single quotes, and put single quotes into double quotes
    # the string $'b is then quoted as '$'"'"'b'
    return b"'" + s.replace(b"'", b"'\"'\"'") + b"'"
Return a shell-escaped version of the string `s`.
bin/scp.py