evmlogger(1M)evmlogger(1M)NAMEevmlogger - Event Manager logger
config_file] log_file] info_file]
The Event Manager (EVM) logger is started automatically by the EVM dae‐
mon at startup. It reads from its configuration file, It reads a set
of definitions of event logs and forwarding information, each with its
own filter string. The logger combines the individual filter strings
to produce a single compound string, connects to the EVM daemon, and
uses the compound filter string to establish its event subscription.
The logger then writes each incoming event to each of the event logs.
The logger may also write the incoming event to forwarders whose indi‐
vidual filter string it matches.
Sets the configuration file to
config_file. The default is
Sets message output to
log_file. The default is When the logger starts, it
renames any previous message file by appending to its
name, and creates a new file.
Specifies the name of an output file to hold summary details of the
current run session.
By default, the logger reads its configuration from To specify a dif‐
ferent configuration file, use the command. If the logger's configura‐
tion file is changed while the logger is running, use the command to
instruct the logger to reconfigure itself. See evmreload(1M).
The logger reconfigures itself when is run, or upon receipt of a sig‐
There is no limit to the number of instances of the logger which may be
running. Individual users or applications can make use of it to monitor
and log interesting events. However, they must provide their own con‐
Secondary logger configuration files can be used to add event logs or
forwarders without modifying the primary configuration file, The loca‐
tion of secondary configuration files is specified in the primary con‐
figuration file by using the keyword. The default (and recommended)
The logger searches the named directory and any subdirectories for
files with names ending in The logger processes the configuration lines
in those files in the same way it processes lines in the primary con‐
A syntax error found in a secondary configuration file results in an
error message and the rejection of the file. However, rejection of one
file does not prevent the primary configuration file or any other sec‐
ondary files from being processed.
It is important that secondary logger configuration files or directo‐
ries are given appropriate permissions because the logger is run with
privileges and can execute commands specified in any secondary configu‐
ration file. The logger rejects any configuration files that are not
properly secure and posts a warning event. See evmlogger.conf(4) for
details of acceptable permissions.
Event logs may be files or terminal devices. If a terminal device is
given as a log, the logger automatically formats the event for display.
If a log is a file or any device other than a terminal, and the log is
not specified as a formatted log, the logger writes events to it in
canonical (binary) form.
If a log is a disk file, the logger creates the file if necessary. If
the log file name ends with the characters the logger replaces that
suffix with the current date in the form yyyymmdd, and begins a new
file when the first event is written to the log each day. A lock file
with a suffix of is created to protect the log file while it is being
A log can be configured to start a new file when it reaches a certain
size. Successive generations of the same log are given the suffix
where is the generation number of the file. A generation control file,
with a suffix of is created to control the generation sequence.
If the logger is writing to the log file, and the file becomes unavail‐
able or unwritable for any reason, the logger switches to the alternate
log file if one has been configured. Otherwise the log is disabled.
If the logger is writing to the alternate log, and the error condition
that caused it to switch has been cleared, you can revert to the pri‐
mary path by using the command.
If a command is specified, the logger executes the command when any
incoming event matches the forwarding filter. The logger then pipes
the incoming event into the command's stream.
The logger executes forwarding commands asynchronously and continues to
handle events while commands are running. However, to ensure proper
sequencing, the logger allows only one instance of each command to run
at a time. If a command is running and another event arrives that
matches the forwarder's filter, the event is queued until the command
terminates. At which time the logger reruns it with the next queued
event. The size of each forwarder's queue is limited and is controlled
using the keyword. To minimize the chances of queuing or missing
events, avoid using the forwarding facility to run commands that may
take significant time to execute. See evmlogger.conf(4) for more
information on setting the queue limit.
By default, only events posted through the local EVM daemon are handled
by the logger's event logs and forwarders.
If an incoming event matches the suppression filter associated with an
event log or forwarder, the event is considered for suppression. For
an event log, suppressing an event reduces the risk of wasting file
storage space by logging repeated instances of the same event. For a
forwarder, suppressing an event reduces the risk of sending replicated
mail messages reporting the same event over a short period. For a full
discussion of the configuration values which control suppression see
The following exit values are returned:
An error occurred.
Default logger configuration file Error log Run information file
kill(1), evmchmgr(1M), evmd(1M), evmget(1), evmreload(1M), evmshow(1),