Viewing logs uses Bunyan for its logs.

Bunyan comes with a command-line tool which can format your logs’ JSON into something much prettier.

Installing the Bunyan CLI

The Bunyan CLI can be installed with npm:

$ sudo npm install -g bunyan

Viewing your logs

To view your logs, just invoke the Bunyan CLI with the log filename specified in your, or pipe from stdin.

For example, to just pretty-print’s output:

$ pump 2>&1 | bunyan


You need 2>&1 because prints logs to stderr.

Or, if your logs are stored at /var/log/

$ bunyan /var/log/

Bunyan logfiles can get quite large and bunyan can take a while to format large files, so it may be smart to only view the latest logs:

$ tail /var/log/ | bunyan

Filtering logs

Bunyan logs are structured. You can filter them to only show (for example) certain types of messages using the -l flag.

Valid loglevels are fatal, error, warn, info, and debug. See the Bunyan documentation for details on what these levels mean, and note that does not use the trace loglevel at all.

For example, if we wanted to show only fatal and error messages:

$ bunyan -l error


if you’re trying to view debug messages but aren’t seeing any, is probably not writing debug log messages. Try adjusting the logLevel config option.

The Bunyan CLI has more options for filtering and output: you can see them by invoking bunyan --help.