Produce a usage error on an invalid signal argument. For example,
$ timeout --signal=invalid 1 sleep 0
timeout: 'invalid': invalid signal
Try 'timeout --help' for more information.
Return an error when a negative interval is provided as the argument
to `uucore::parse_time::from_str()`, since a `Duration` should only be
non-negative.
Use `Duration::saturating_mul()` to avoid a panic due to overflow in
`uucore::parse_time::from_str()`. This change prevents panic on very
large arguments to timeout and sleep.
Fix a bug where `timeout --preserve-status` was not correctly
preserving the status code of the child process if it timed out. When
that happens, the status code of the child process is considered to be
the signal number (in this case, `SIGTERM`). The exit status of
`timeout` is then 128 plus the numeric code associated with `SIGTERM`.
To prevent clap from parsing flags for the command to run as flags for
timeout, remove the "args" positional argument, but allow to pass flags
via the "command" positional arg.
