# bunyan(1) -- filter and pretty-print Bunyan log file content


## SYNOPSIS

`bunyan` \[OPTIONS\]

... | `bunyan` \[OPTIONS\]

`bunyan` \[OPTIONS\] -p PID


## DESCRIPTION

"Bunyan" is **a simple and fast a JSON logging library** for node.js services,
a one-JSON-object-per-line log format, and **a `bunyan` CLI tool** for nicely
viewing those logs. This man page describes the latter.


### Pretty-printing

A bunyan log file is a stream of JSON objects, optionally interspersed with
non-JSON log lines. The primary usage of bunyan(1) is to pretty print,
for example:

    $ bunyan foo.log          # or `cat foo.log | bunyan
    [2012-02-08T22:56:52.856Z]  INFO: myservice/123 on example.com: My message
        extra: multi
        line
    [2012-02-08T22:56:54.856Z] ERROR: myservice/123 on example.com: My message
    ...

By default the "long" output format is used. Use the `-o FORMAT` option to
emit other formats. E.g.:

    $ bunyan foo.log -o short
    22:56:52.856Z  INFO myservice: My message
        extra: multi
        line
    22:56:54.856Z ERROR myservice: My message
    ...

These will color the output if supported in your terminal.
See "OUTPUT FORMATS" below.


### Filtering

The `bunyan` CLI can also be used to filter a bunyan log. Use `-l LEVEL`
to filter by level:

    $ bunyan foo.log -l error       # show only 'error' level records
    [2012-02-08T22:56:54.856Z] ERROR: myservice/123 on example.com: My message

Use `-c COND` to filter on a JavaScript expression returning true on the
record data. In the COND code, `this` refers to the record object:

    $ bunyan foo.log -c `this.three`     # show records with the 'extra' field
    [2012-02-08T22:56:52.856Z]  INFO: myservice/123 on example.com: My message
        extra: multi
        line


## OPTIONS

  * `-h`, `--help`:
    Print this help info and exit.

  * `--version`:
    Print version of this command and exit.

  * `-q`, `--quiet`:
    Don't warn if input isn't valid JSON.

Dtrace options (only on dtrace-supporting platforms):

  * `-p PID`, `-p NAME`:
    Process bunyan:log-\* probes from the process with the given PID.
    Can be used multiple times, or specify all processes with '\*',
    or a set of processes whose command & args match a pattern with
    '-p NAME'.

Filtering options:

  * `-l`, `--level LEVEL`:
    Only show messages at or above the specified level. You can specify level
    *names* or numeric values. (See 'Log Levels' below.)

  * `-c COND`, `--condition COND`:
    Run each log message through the condition and only show those that
    resolve to a truish value. E.g. `-c 'this.pid == 123'`.

  * `--strict`:
    Suppress all but legal Bunyan JSON log lines. By default non-JSON, and
    non-Bunyan lines are passed through.

Output options:

  * `--color`:
    Colorize output. Defaults to try if output stream is a TTY.

  * `--no-color`:
    Force no coloring (e.g. terminal doesn't support it)

  * `-o FORMAT`, `--output FORMAT`:
    Specify an output format. One of `long` (the default), `short`, `json`,
    `json-N`, `bunyan` (the native bunyan 0-indent JSON output) or `inspect`.

  * `-j`:
    Shortcut for `-o json`.


## LOG LEVELS

In Bunyan log records, then `level` field is a number. For the `-l|--level`
argument the level **names** are supported as shortcuts. In `-c|--condition`
scripts, uppercase symbols like "DEBUG" are defined for convenience.

    Level Name      Level Number    Symbol in COND Scripts
    trace           10              TRACE
    debug           20              DEBUG
    info            30              INFO
    warn            40              WARN
    error           50              ERROR
    fatal           60              FATAL


## OUTPUT FORMATS

    FORMAT NAME         DESCRIPTION
    long (default)      The default output. Long form. Colored and "pretty".
                        'req' and 'res' and 'err' fields are rendered specially
                        as an HTTP request, HTTP response and exception
                        stack trace, respectively. For backward compat, the
                        name "paul" also works for this.
    short               Like the default output, but more concise. Some
                        typically redundant fields are ellided.
    json                JSON output, 2-space indentation.
    json-N              JSON output, N-space indentation, e.g. "json-4"
    bunyan              Alias for "json-0", the Bunyan "native" format.
    inspect             Node.js `util.inspect` output.


## DTRACE SUPPORT

On systems that support DTrace (e.g., MacOS, FreeBSD, illumos derivatives
like SmartOS and OmniOS), Bunyan will create a DTrace provider (`bunyan`)
that makes available the following probes:

    log-trace
    log-debug
    log-info
    log-warn
    log-error
    log-fatal

Each of these probes has a single argument: the string that would be
written to the log.  Note that when a probe is enabled, it will
fire whenever the corresponding function is called, even if the level of
the log message is less than that of any stream.

See <https://github.com/trentm/node-bunyan#dtrace-support> for more details
and the '-p PID' option above for convenience usage.


## ENVIRONMENT

  * `BUNYAN_NO_COLOR`:
    Set to a non-empty value to force no output coloring. See '--no-color'.


## PROJECT & BUGS

`bunyan` is written in JavaScript and requires node.js (`node`). The project
lives at <https://github.com/trentm/node-bunyan> and is published to npm as
"bunyan".

* README, Install notes: <https://github.com/trentm/node-bunyan#readme>
* Report bugs to <https://github.com/trentm/node-bunyan/issues>.
* See the full changelog at: <https://github.com/trentm/node-bunyan/blob/master/CHANGES.md>


## LICENSE

MIT License (see <https://github.com/trentm/node-bunyan/blob/master/LICENSE.txt>)


## COPYRIGHT

node-bunyan is Copyright (c) 2012 Joyent, Inc. Copyright (c) 2012 Trent Mick.
All rights reserved.
