Controls an already supervised *service* at live defined in a *tree*.
## Interface
```
66-svctl [ -h ] [ -z ] [ -v verbosity ] [ -l live ] [ -t tree ] [ -T timeout ] [ -n death ] [ -u | d | r | K | X ] service(s)
```
This tool expects to find an already supervised *service* at *live* defined in the given *tree* and an already running [scandir](66-scandir.html).
***(!)*** This tool only deals with `classic` services—see [66‑dbctl](66-dbctl.html) for other types of services.
Multiple *services* can be handled by separating their names with a space. *66‑svctl* gathers each of these services in a list called *selection*. The command is sent to the *selection* asynchronously.
## Exit codes
-*0* success
-*100* wrong usage
-*111* system call failed
## Options
-**-h** : prints this help.
-**-z** : use color.
-**-v***verbosity* : increases/decreases the verbosity of the command.
**1* : only print error messages. This is the default.
**2* : also print warning messages.
**3* : also print tracing messages.
**4* : also print debugging messages.
-**-l***live* : changes the supervision directory of *service* to *live*. By default this will be `%%livedir%%`. The default can also be changed at compile time by passing the `--livedir=live` option to `./configure`. An existing absolute path is expected and should be within a writable and executable filesystem - likely a RAM filesystem—see [66-scandir](66-scandir.html).
-**-t** : handles the *selection* of the given *tree*. This option is mandatory except if a tree was marked as 'current'—see [66-tree](66-tree.html).
-**-T***timeout* : specify a timeout in milliseconds after which *66-svctl* will stop trying to reach the desired state of the *service*; defaults to `3000`. timeout is applied to each *service* of the *selection*. Separate timeouts for different services can be set in their respective [frontend](frontend.html) files using the `@timeout‑up` or `@timeout‑down` key. The [frontend](frontend.html) key is prioritized over this option.
-**-n***death* : specifiy the maximum number of *service* death events that the supervisor will keep track of. If the *service* dies more than this number of times *66‑svctl* will stop trying to reach the desired state of the *service*. The [frontend](frontend.html) key `@maxdeath` is prioritized over this option—see [frontend](frontend.html). If this option is not specified and no max-death-tally file exists then the maximum allowed deaths will be `5` by default.
-**-u** : send an up signal to *service*. It searches for a notification-fd file—see [service startup notifications](https://skarnet.org/software/s6/notifywhenup.html) and [frontend](frontend.html). If this file exists *66‑svctl* will automatically change to uppercase `U`.
-**-d** : send a down signal to *service*. It searches for a notification‑fd file—see [service startup notifications](https://skarnet.org/software/s6/notifywhenup.html) and [frontend](frontend.html). If this file exists *66‑svctl* will automatically change to uppercase `D`.
-**-r** : send a reload signal to *service*. By default the signal is a `SIGTERM`; this can be configured with the `@down-signal` field in the [frontend](frontend.html) service file. It searches for a notification-fd file—see [service startup notifications](https://skarnet.org/software/s6/notifywhenup.html) and [frontend](frontend.html). If this file exists *66‑svctl* will automatically change to uppercase `R`.
-**-X** : exit; the supervisor of the *service* will exit too. This command should normally never be used on a working system.
-**-K** : send a SIGKILL to *service* and keep it down.
## s6-svc corresponding signal
The *66‑svctl* signals correspond to [s6‑svc](https://skarnet.org/software/s6/s6-svc.html) in the following manner:
-*-u* = -u
-*-U* = -uwU
-*-d* = -d
-*-D* = -uwD
-*-r* = -r
-*-X* = -xd
-*-K* = -kd
## Notes
You can also send a signal in a similar fashion to a `classic` or `longrun` service with the [s6‑svc](https://skarnet.org/software/s6/s6-svc.html) tool which has the philosophy "launch and forget" which unlike *66‑svctl* does not care for the exit status of the service when a signal is sent.
As an extra convenience the **-n** option allows to deal directly with *max-death-tally* from the command line even if it was not specified explicitely in the services [frontend](frontend.html) file and no corresponding file exists.
This command expects to find an already supervised *service* and an already running [scandir](scandir.html).
This command is the heart of `66` concerning service state change. Every other `66` command that need to send a signal to a service pass through this command.
Multiple *services* can be handled by separating their names with a space.
## Options
-**-h**: print this help.
-**-P**: Do not handle service dependencies. In such cases, the *signal* command will not attempt to send signal to the services that are dependent on the service, regardless of their current state.
-**-wu**: do not exit until the service is up.
-**-wU**: do not exit until the service is up and ready and has notified readiness.
-**-wd**: do not exit until the service is down.
-**-wD**: do not exit until the service is down and ready to be brought up and has notified readiness.
-**-wr**: do not exit until the service has been started or restarted.
-**-wR**: do not exit until the service has been started or restarted and has notified readiness.
-**-a**: send a SIGALRM signal.
-**-b**: send a SIGABRT signal.
-**-q**: send a SIGQUIT signal.
-**-H**: send a SIGHUP signal.
-**-k**: send a SIGKILL signal.
-**-t**: send a SIGTERM signal.
-**-i**: send a SIGINT signal.
-**-1**: send a SIGUSR1 signal.
-**-2**: send a SIGUSR2 signal.
-**-p**: send a SIGSTOP signal.
-**-c**: send a SIGCONT signal.
-**-y**: send a SIGWINCH signal.
-**-o**: once. Equivalent to '-uO'.
-**-d**: send a SIGTERM signal then a SIGCONT signal.
-**-D**: bring down service and avoid to be bring it up automatically.
-**-u**: bring up service.
-**-U**: bring up service and ensure that service can be restarted automatically.
-**-x**: bring down the service and propagate to its supervisor.
-**-O**: mark the service to run once at most.
-**-r**: restart service by sending it a signal(default SIGTERM).
## Usage examples
Send a SIGHUP signal to `foo`
```
66 signal -H foo
```
Send a SIGHUP signal to `foo` by signal name
```
66 signal -s SIGHUP foo
```
Triggers a log rotation of `foo-log`
```
66 signal -a -P foo-log
```
Take down `foo` and block until the process is down and the finish script has completed
```
66 signal -wD -d foo
```
Bring up `foo` and block until it has sent notification that it is ready. Exit if it is still not ready after 5 seconds.
