log(1)

NAME
log - Access system wide log messages created by os_log, os_trace and other logging systems.

SYNOPSIS
log [command [options]]

log help [command]

log collect [--output path] [--start date/time] [--size num [k|m]] [--last num [m|h|d]] [--device | --device-name name | --device-udid UDID]

log config [--reset | --status] [--mode mode(s)] [--subsystem name [--category name]] [--process pid]

log erase [--all] [--ttl]

log show [--archive archive | --file file] [--predicate filter] [--source] [--style default | compact | json | ndjson | syslog] [--color auto | always | none] [--start date/time] [--end date/time] [--[no-]info] [--[no-]debug] [--[no-]pager] [--[no-]signpost] [--last time [m|h|d]] [--timezone local | timezone]

log stats [--archive archive] [--sort events | bytes] [--count count | all] [--overview | --per-book | --per-file | --sender sender | --process process | --predicate predicate]

log stream [--level default | info | debug] [--process pid | process] [--predicate filter] [--source] [--style default | compact | json | syslog] [--color auto | always | none] [--timeout time [m|h|d]] [--type activity | log | trace]

DESCRIPTION
log is used to access system wide log messages created by os_log, os_trace and other logging systems. Some commands require root privileges.

Available commands and their options:

help
    General help or help specific to command argument

collect
    Collect the system logs into a .logarchive that can be viewed later with tools such as log or Console. If an output path is not specified, system_logs.logarchive will be created in the current directory.

    --output path
        Save the archive to the specified path or file. If the path is a directory, a file named system_logs.logarchive will be created in the specified directory. If the path contains the extension .logarchive, a new logarchive will be created with that name at the specified path.

    --start date/time
        Limits the content capture to the date and time forward to now. The following date/time formats are accepted: "YYYY-MM-DD", "YYYY-MM-DD HH:MM:SS", "YYYY-MM-DD HH:MM:SSZZZZZ"

    --last num [m|h|d]
        Limits the captured events to the period starting at the given interval ago from the current time. Time is assumed in seconds unless specified. Example: "--last 2m" or "--last 3h"

    --size num [k|m]
        The amount of data to be captured in kilobytes or megabytes. This is an approximation, as the actual size may be more than requested. Example: "--size 100k" or "--size 20m"

    --device
        Collect system logs from paired device (first device found).

    --device-name name
        Collect system logs from paired device with the given name.

    --device-udid UDID
        Collect system logs from paired device with the given UDID.

config
    Configure, reset or read settings for the logging system. config commands can act system-wide or on a subsystem. If not specified, system-wide is assumed. If subsystem is specified, category is optional. Requires root access.

    --reset | --status
        Option to show or reset the current settings for the system or a specific subsystem. If reset or status is not specified, a change to the configuration is assumed. For example, "log config --reset --subsystem com.mycompany.mysubsystem" will reset the subsystem to its default settings. "log config --status" will show the current system-wide logging settings. "log config --mode "level: default"" will set the system log level to default.

    --subsystem name
        Set or get mode for a specified subsystem.

    --category name
        Set or get mode for a specified category. If category is supplied, subsystem is required.

    --process pid
        Set mode for a specified pid.

    --mode mode(s)
        Will enable given mode. Modes include:

        level: {off | default | info | debug} The level is a hierarchy, e.g. debug implies debug, info, and default.

        persist: {off | default | info | debug} The persist mode is a hierarchy, e.g. debug implies debug, info, and default.

erase
    Delete selected log data from the system. If no arguments are specified, the main log datastore and inflight log data will be deleted.

    --all
        Deletes main log datastore, and inflight log data as well as time-to-live data (TTL), and the fault and error content.

    --ttl
        Deletes time-to-live log content.

show
    Shows contents of the system log datastore, archive or a specific tracev3 file. If a file or archive is not specified, the system datastore will be shown. If it is from a future system version that log cannot understand, it exists with EX_DATAERR (65) and an error message. The output contains only default level messages unless --info and/or --debug are specified. The output does not contain signposts unless --signpost is specified.

    --archive archive
        Display events stored in the given archive. The archive must be a valid log archive bundle with the suffix .logarchive.

    --file file
        Display events stored in the given .tracev3 file. In order to be decoded, the file must be contained within a valid .logarchive bundle, or part of the system logs directory.

    --[no-]pager
        Enable or disable pagination of output via less.

    --predicate filter
        Filters messages based on the provided predicate, based on NSPredicate. A compound predicate or multiple predicates can be provided. See section "PREDICATE-BASED FILTERING" below.

    --source
        Include symbol names and source line numbers for messages, if available.

    --style style
        Control the output formatting of events:

        default
            Human readable output. ISO-8601 date (microsecond precision and timezone offset), thread ID, log type, activity ID, process ID, TTL, process, subsystem, category and message content.

        compact
            Compact human readable output. ISO-8601 date (millisecond precision), abbreviated log type, process, processID, thread ID, subsystem, category and message content. This output uses less horizontal space to indicate event metadata than the default style.

        json
            JSON output. Event data is synthesized as an array of JSON dictionaries.

        ndjson
            Line-delimited JSON output. Event data is synthesized as JSON dictionaries, each emitted on a single line. A trailing record, identified by the inclusion of a "finished" field, is emitted to indicate the end of events.

        syslog
            syslog-style output intended to be more compatible with the output format used by syslog(1).

    --color auto | always | none
        Control the display of colorized output. By default, log(1) will disable colorized output when not directed to a terminal, unless overidden using always.

    --start date/time
        Shows content starting from the provided date. The following date/time formats are accepted: "YYYY-MM-DD", "YYYY-MM-DD HH:MM:SS", "YYYY-MM-DD HH:MM:SSZZZZZ"

    --end date/time
        Shows content up to the provided date. The following date/time formats are accepted: "YYYY-MM-DD", "YYYY-MM-DD HH:MM:SS", "YYYY-MM-DD HH:MM:SSZZZZZ"

    --last time[m|h|d] | boot
        Shows events that occurred within the given time relative to the end of the log archive, or beginning at the last boot contained within the log archive. Time may be specified as minutes, hours or days. Time is assumed in seconds unless specified. Example: "--last 2m" or "--last 3h"

    --timezone local | timezone
        Displays content in the local timezone, or a specified timezone (see tzset(3)). If not specified, the output is displayed in the timezone at the time the entry was written to source archive or file.

    --[no-]info
        Disable or enable info level messages in the output. (By default info messages are not displayed.)

    --[no-]debug
        Disable or enable debug level messages in the output. (By default debug messages are not displayed.)

    --[no-]signpost
        Disable or enable display of signposts in the output. (By default signposts are not displayed.)

stats
    Shows a breakdown of the events contained within a log datastore or archive. The following options can be supplied to all modes of log stats:

    --archive archive
        Display statistics for events stored in the given archive. The archive must be a valid log archive bundle with the suffix .logarchive.

    --sort events | bytes
        Sort tabulated data output by number of events, or number of bytes.

    --count count | all
        Limit tabulated data to the given number of lines, or all displays all entries in tables.

    --style human | json
        Control the format style of the requested output mode.

    In addition, one of the following output modes can be supplied:

    --overview
        Displays statistics for the entire archive.

    --per-book
        Displays statistics per log book, the subsections of a log archive.

    --per-file
        Displays statistics per file in the archive.

    --sender sender
        Displays statistics for a given sender image name.

    --process process
        Displays statistics for a given originating process.

    --predicate predicate
        Displays statistics for all events matching the given predicate.

stream
    Stream activities, log data or trace messages for the system or from a given process. By default, the command assumes system-wide streaming. Specifying a process id with the --process option will narrow the results.

    --level default | info | debug
        Shows messages at specified level and below. The level is a hierarchy. Specifying debug implies debug, info and default.

    --predicate filter
        Filters messages using the provided predicate based on NSPredicate. A compound predicate or multiple predicates can be provided. See section "PREDICATE-BASED FILTERING" below.

    --process pid | process
        The process on which to operate. This option can be passed more than once to operate on multiple processes.

    --style default | compact | json | syslog
        Output the content as a different style.

    --color auto | always | none
        Highlight certain types of log messages. In auto, highlighting will be disabled if the output is detected to be non-TTY.

    --source
        Include symbol names and source line numbers for messages, if available.

    --timeout time [m|h|d]
        Timeout the stream operation after a specified time, e.g. "--timeout 5m", "--timeout 1h" If minutes, hours, days not specified, seconds will be used.

    --type activity | log | trace
        Dictates the type of events to stream from a process. By default all types are streamed unless otherwise specified. Pass an appropriate --type for each requested type of event.

PREDICATE-BASED FILTERING
Using predicate-based filters via the --predicate option allows users to focus on messages based on the provided filter criteria. For detailed information on the use of predicate based filtering, please refer to the Predicate Programming Guide: https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Predicates/Articles/pSyntax.html

The filter argument defines one or more pattern clauses following NSPredicate rules. See log help predicates for the full list of supported keys. Supported keys include:

eventType
    The type of event: activityCreateEvent, activityTransitionEvent, logEvent, signpostEvent, stateEvent, timesyncEvent, traceEvent and userActionEvent.

eventMessage
    The pattern within the message text, or activity name of a log/trace entry.

messageType
    For logEvent and traceEvent, the type of the message itself: default, info, debug, error or fault.

process
    The name of the process the originated the event.

processImagePath
    The full path of the process that originated the event.

sender
    The name of the library, framework, kernel extension, or mach-o image, that originated the event.

senderImagePath
    The full path of the library, framework, kernel extension, or mach-o image, that originated the event.

subsystem
    The subsystem used to log an event. Only works with log messages generated with os_log(3) APIs.

category
    The category used to log an event. Only works with log messages generated with os_log(3) APIs. When category is used, the subsystem filter should also be provided.

PREDICATE-BASED FILTERING EXAMPLES
Filter for specific subsystem:
 log show --predicate 'subsystem == "com.example.my_subsystem"'

Filter for specific subsystem and category:
 log show --predicate '(subsystem == "com.example.my_subsystem") && (category == "desired_category")'

Filter for specific subsystem and categories:
 log show --predicate '(subsystem == "com.example.my_subsystem") && (category IN { "category1", "category2" })'

Filter for a specific subsystem and sender(s):
 log show --predicate '(subsystem == "com.example.my_subsystem") && ((senderImagePath ENDSWITH "mybinary") || (senderImagePath ENDSWITH "myframework"))'

PREDICATE-BASED FILTERING EXAMPLES WITH LOG LINE

log show system_logs.logarchive --predicate 'subsystem == "com.example.subsystem" and category contains "CHECK"'

Timestamp                       Thread     Type        Activity     PID
2016-06-13 11:46:37.248693-0700 0x7c393    Default     0x0          10371  timestamp: [com.example.subsystem.CHECKTIME] Time is 06/13/2016 11:46:37

log show --predicate 'processImagePath endswith "hidd" and senderImagePath contains[cd] "IOKit"' --info

Timestamp                       Thread     Type        Activity     PID
2016-06-10 13:54:34.593220-0700 0x250      Info        0x0          113    hidd: (IOKit) [com.apple.iohid.default] Loaded 6 HID plugins

ENVIRONMENT
The following environment variables affect the execution of log:

LOG_COLORS
    Controls the color of text output from log show. This string is a concatenation of pairs of the format fb, where f is the foreground color and b is the background color.

    The color designators are as follows:

    a   black
    b   red
    c   green
    d   brown
    e   blue
    f   magenta
    g   cyan
    h   light grey
    A   bold black, usually shows up as dark grey
    B   bold red
    C   bold green
    D   bold brown, usually shows up as yellow
    E   bold blue
    F   bold magenta
    G   bold cyan
    H   bold light grey; looks like bright white
    x   default foreground or background

    Note that the above are standard colors. The actual display may differ depending on the color capabilities of the terminal in use.

    The order of the attributes are as follows:

    1.  timestamp
    2.  thread identifier
    3.  event type
    4.  activity identifier
    5.  process identifier
    6.  time-to-live
    7.  process name
    8.  sender image name
    9.  subsystem
    10. category
    11. event message
    12. highlight color

    The default is "xxxxxxxxxxxxFxdxcxExxxxA", i.e. bold magenta process name, yellow sender, green subsystem, bold blue category and dark grey background for highlighted lines.

LOG_STYLE
    Control the default output style of log show: default, compact, json or syslog.

OS_ACTIVITY_MODE
    Change the mode of launched processes to:
    info
        Enables info level messages. Does not override logging Preferences that have info level disabled.
    debug
        Enables debug level messages which includes info level messages. Does not override logging Preferences that have info level or debug level disabled.

OS_ACTIVITY_STREAM
    Change the type of streaming enabled.
    live
        Live streaming from the process using IPC.

OS_ACTIVITY_PROPAGATE_MODE
    If set, will propagate the mode settings via activities.

FILES
You can control the execution of log show and log stream with a configuration file located at ~/.logrc. Given a ~/.logrc like this:

    # .logrc - default log(1) arguments, handy predicate shortcuts
    show:
        --style compact
        --last 1h
        --info      # turn back off with --no-info
        --no-debug  # turn back on with --debug
    predicate:
        app 'process == "application"'
        errors 'process == "application" and messageType == error'
        s
            'process == "application" and '         # adjacent strings
            'subsystem == "com.example.support"'    # get merged

log show would automatically run as though the arguments

    --style compact --last 1h --info --no-debug

were passed in. Explicit options will override the arguments provided by ~/.logrc. Furthermore, running with --predicate app would be the same as using:

    --predicate 'process == "application"'

The syntax of the ~/.logrc file made of comments, section headers, options, words, and single-quoted strings. Comments start with the hash character and run to the end of the line. Otherwise, contents are whitespace-separated.

The structure of the ~/.logrc file is broken into sections. Section headers are specified by a word and a colon. There are three kinds of sections. The show: and stream: sections operate similarly. Their contents are literal options and arguments that will be passed to the respective command as if they were entered on the command line. The predicate: section creates aliases for predicates. It is made up of pairs of:

word ' predicate '

where word is a combination of letters (presumably a simple, easy-to-type one) and predicate is some filtering logic, as described in the PREDICATE-BASED FILTERING section above. The predicate is delimited by single quotes, but adjacent quoted elements are "glued" together; this helps in making long predicates easier to read and write.

SEE ALSO
os_log(3), os_trace(3)