# Command Line Option

This article describes built-in commands and its options

## fluentd

Invoke fluentd. Here is supported options:

```
Usage: fluentd [options]
    -s, --setup [DIR=/etc/fluent]    install sample configuration file to the directory`
    -c, --config PATH                config file path (default: /etc/fluent/fluent.conf)
        --dry-run                    Check fluentd setup is correct or not
    -p, --plugin DIR                 add plugin directory
    -I PATH                          add library path
    -r NAME                          load library
    -d, --daemon PIDFILE             daemonize fluent process
        --no-supervisor              run without fluent supervisor
        --user USER                  change user
        --group GROUP                change group
    -o, --log PATH                   log file path
    -i CONFIG_STRING,                inline config which is appended to the config file on-fly
        --inline-config
        --emit-error-log-interval SECONDS
                                     suppress interval seconds of emit error logs
        --suppress-repeated-stacktrace [VALUE]
                                     suppress repeated stacktrace
        --without-source             invoke a fluentd without input plugins
        --use-v1-config              Use v1 configuration format (default)
        --use-v0-config              Use v0 configuration format
    -v, --verbose                    increase verbose level (-v: debug, -vv: trace)
    -q, --quiet                      decrease verbose level (-q: warn, -qq: error)
        --suppress-config-dump       suppress config dumping when fluentd starts
    -g, --gemfile GEMFILE            Gemfile path
    -G, --gem-path GEM_INSTALL_PATH  Gemfile install path (default: $(dirname $gemfile)/vendor/bundle)
```

### Important options

#### --suppress-config-dump

Fluentd starts without configuration dump. If you don't want to show configuration in fluentd logs, e.g. don't show private keys, this options is useful.

#### --suppress-repeated-stacktrace

If set true, suppress stacktrace in fluentd logs. Since v0.12, this option is true by default.

#### --without-source

Fluentd starts without input plugins. This option is useful for flushing buffers with no new incoming events.

#### -i, --inline-config

If you use fluentd on XaaS which doesn't support persistent disks, this option is useful.

#### --no-supervisor

If you want to use your supervisor tools, this option avoids double supervisor.

### Set via configuration file

Several options could be set via `<system>` directive configuration file. See [configuration file article](https://docs.fluentd.org/0.12/configuration/config-file#4-set-system-wide-configuration-the-ldquosystemrdquo-directive).

## fluent-cat

Send event to fluentd's `in_forward`/`in_unix` plugin. This is useful for testing.

```
Usage: fluent-cat [options] <tag>
    -p, --port PORT                  fluent tcp port (default: 24224)
    -h, --host HOST                  fluent host (default: 127.0.0.1)
    -u, --unix                       use unix socket instead of tcp
    -s, --socket PATH                unix socket path (default: /var/run/fluent/fluent.sock)
    -f, --format FORMAT              input format (default: json)
        --json                       same as: -f json
        --msgpack                    same as: -f msgpack
        --none                       same as: -f none
        --message-key KEY            key field for none format (default: message)
```

### example

Send json message with `debug.log` tag to local fluentd:

```
% echo '{"message":"hello"}' | fluent-cat debug.log
```

Send to other machine:

```
% echo '{"message":"hello"}' | fluent-cat debug.log --host testserver --port 24225
```

If this article is incorrect or outdated, or omits critical information, please [let us know](https://github.com/fluent/fluentd-docs-gitbook/issues?state=open). [Fluentd](http://www.fluentd.org/) is a open source project under [Cloud Native Computing Foundation (CNCF)](https://cncf.io/). All components are available under the Apache 2 License.