main/tools/fx/cmd/log.md

# fx log

Display logs from a target device.

```none
usage: fx log FFX_LOG_FLAGS

   FFX_LOG_FLAGS           flags to pass to ffx log, see `fx ffx log --help`.

LEGACY MODE: listen for logs from the on-device log_listener

usage: fx log --legacy [-h | --help] [--raw] LOG_LISTENER_FLAGS

   --legacy                runs in legacy mode, i.e. listen for logs from
                           the on-device log_listener

   --raw                   do not attempt to symbolize the log

   --help|-h               show this help and attempt to also show the
                           on-device log_listener help

   LOG_LISTENER_FLAGS      flags (e.g., severity) to pass to the on-device
                           log_listener; supported flags are listed at
                           https://fuchsia.dev/fuchsia-src/reference/diagnostics/consumers/log_listener.

Creates an SSH connection with a device and starts listening for logs.
It will listen to the device specified with `fx -t DEVICE log` or
`fx set-device`, otherwise it will try to find a connected device.

If the command hangs without printing anything, first check to make sure `fx shell`
works on its own.

For more information on flags supported by the on-device log_listener, see
https://fuchsia.dev/fuchsia-src/reference/diagnostics/consumers/log_listener.
```

[log source code](https://cs.opensource.google/fuchsia/fuchsia/+/main:tools/devshell/log)