svcadm(1M)을 검색하려면 섹션에서 1M 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
logadm(8)
System Administration Commands logadm(8)
NAME
logadm - manage endlessly growing log files
SYNOPSIS
logadm [-options] [logname]...
DESCRIPTION
logadm is a general log rotation tool that is suitable for running from
cron(8).
Without arguments, logadm reads the /etc/logadm.conf file, and for
every entry found in that file checks the corresponding log file to see
if it should be rotated. Typically this check is done each morning by
an entry in the root's crontab.
If the logname argument is specified, logadm renames the corresponding
log file by adding a suffix so that the most recent log file ends with
.0 (that is, logfile.0), the next most recent ends with .1 (that is,
logfile.1), and so forth. By default, ten versions of old log files are
kept (that is, logfile.0 through logfile.9). At the point when what
would be the eleventh file is logged, logadm automatically deletes the
oldest version to keep the count of files at ten.
logadm takes a number of options. You can specify these options on the
command line or in the /etc/logadm.conf file. The logadm command
searches /etc/logadm.conf for lines of the form logname options
logname
Identifies an entry in /etc/logadm.conf. This can be a name or the
pathname of the log file. If you specify a log file, rather than a
name, for this field, it must be a fully qualified pathname.
options
Identifies command line options exactly as they would be entered on
the command line. This allows commonly used log rotation policies
to be stored in the /etc/logadm.conf file. See EXAMPLES.
If options are specified both in /etc/logadm.conf and on the com‐
mand line, those in the /etc/logadm.conf file are applied first.
Therefore, the command line options override those in
/etc/logadm.conf.
Log file names specified in /etc/logadm.conf may contain filename
substitution characters such as * and ?, that are supported by
csh(1).
Two options control when a log file is rotated, -p and -s.
When using more than one of these options at a time, there is an
implied and between them. This means that all conditions must be met
before the log is rotated.
If neither of these two options are specified, the default conditions
for rotating a log file are: -s 1b -p 1w, which means the log file
is only rotated if the size is non-zero and if at least 1 week has
passed since the last time it was rotated.
By specifying -p never as a rotation condition, any other rotation
conditions are ignored and logadm moves on to the expiration of old log
files. By specifying -p now as a rotation condition, a log rotation is
forced.
Unless specified by the -o, -g, or -m options, logadm replaces the log
file (after renaming it) by creating an empty file whose owner, group
ID, and permissions match the original file.
Three options control when old log files are expired, -A, -C, and -S.
These options expire the oldest log files until a particular condition
or conditions are met. For example, the combination -C 5 and the -S
10m options expires old log files until there are no more than 5 of the
files and their combined disk usage is no more than 10 megabytes. If
none of these options are specified, the default expiration is -C 10
which keeps ten old log files. If no files are to be expired, use -C 0
to prevent expiration by default.
logadm stores timestamps in the file /var/logadm/timestamps. For users
of previous versions of logadm, the utility automatically moves time‐
stamps from /etc/logadm.conf, their previous repository, to
/var/logadm/timestamps.
OPTIONS
The following options are supported:
-a post_command
Execute the post_command after renaming the log file. post_command
is passed to sh -c.
Specify post_command as a valid shell command. Use quotes to pro‐
tect spaces or shell metacharacters in post_command.
This option can be used to restart a daemon that is writing to the
file. When rotating multiple logs with one logadm command,
post_command is executed only once after all the logs are rotated,
not once per rotated log.
-A age
Delete any versions that have not been modified for the amount of
time specified by age.
Specify age as a number followed by an h (hours), d (days),
w(weeks), m (months), or y (years).
-b pre_command
Execute pre_command before renaming the log file. pre_command is
passed to sh -c.
Specify pre_command as a valid shell command. Use quotes to protect
spaces or shell metacharacters in the pre_command.
This option can be used to stop a daemon that is writing to the
file. When rotating multiple logs with one logadm command, pre_com‐
mand is executed only once before all the logs are rotated, not
once per rotated log.
-c
Rotate the log file by copying it and truncating the original log‐
file to zero length, rather than renaming the file.
This option cannot be used along with -o, -g or -m as the file per‐
missions need to match the owner of the original file being trun‐
cated.
-C count
Delete the oldest versions until there are not more than count
files left.
If no expire options (-A, -C, or -S) are specified, -C 10 is the
default. To prevent the default expire rule from being added auto‐
matically, specify -C 0 .
-e mail_addr
Send error messages by email to mail_addr.
As logadm is typically run from cron(8), error messages are cap‐
tured by cron and mailed to the owner of the crontab.
This option is useful if you want the mail regarding error messages
to go to another address instead. If no errors are encountered, no
mail message is generated.
-E cmd
Execute cmd to expire the file, rather than deleting the old log
file to expire it.
cmd is passed it to sh -c. The file is considered expired after
cmd completes. If the old log file is not removed or renamed by the
cmd, logadm considers it for expiration the next time that it runs
on the specified log file. If present, the keyword $file is
expanded in the specified cmdto the name of the file being expired.
This option is useful for tasks such as mailing old log files to
administrators, or copying old log files to long term storage.
-f conf_file
Use conf_file instead of /etc/logadm.conf.
This option allows non-root users to keep their own logadm configu‐
ration files.
-F timestamp_file
Use timestamp_file instead of /var/logadm/timestamps to store
logadm timestamps.
-g group
Create a new empty file with the ID specified by group, instead of
preserving the group ID of the log file.
Specify group by name or by numeric group ID, as accepted by
chgrp(1).
This option requires the ability to change file group ownership
using the chgrp(1) command.
-h
Print a help message that describes logadm's options.
-l
Use local time rather than the Coordinated Universal Time (UTC)
when naming rotated log files (see the discussion of percent
sequences in the templates supplied with the -t option).
-m mode
Create a new empty file with the mode specified by mode, instead of
preserving the mode of the log file.
Specify mode in any form that is accepted by the chmod(1) command.
-M cmd
Use cmd to rename the log file. If the keyword $file is specified,
it is expanded to the name of the log file. Similarly, the keyword
$nfile is expanded to the new name of the log file. The $nfile key‐
word is only available with commands provided with the -M option.
After the command completes, the log file is replaced by the rotate
file. The default cmd is "/bin/mv $file$nfile".
-n
Print the actions that the logadm command will perform without
actually performing them.
This option is useful for checking arguments before making any
changes to the system.
It is important to remember, however, that since log rotating
actions are only printed with this option, logadm might not find
files that need expiring, but if run without the -n option, logadm
might create a file that needs expiring by performing the log
rotating actions. Therefore, if you see no files being expired with
the -n option, files still might be expired without it.
-N
Prevent an error message if the specified logfile does not exist.
Normally, logadm produces an error message if the log file is not
found. With -N, if the log file doesn't exist logadm moves on to
the expire rules (if any) and then to the next log file (if any),
without creating the empty replacement log file.
-o owner
Create the new empty file with owner, instead of preserving the
owner of the log file.
Specify owner in any form that is accepted by the chown(1) command.
-p period
Rotate a log file after the specified time period (period).
Specify period as a number followed by d for days, h for hours, w
for weeks, m for months (30 days) or y for years. There are also
two special values for period: now and never. "-p now" forces log
rotation. "-p never" forces no log rotation.
-P timestamp
Used by logadm to record the last time the log was rotated in
/var/logadm/timestamps.
This option uses timestamp to determine if the log rotation period
has passed. The format of timestamp matches the format generated by
ctime(3C), with quotes around it to protect embedded spaces. time‐
stamp is always recorded in the Coordinated Universal Time (UTC)
time zone.
-r
Remove any entries corresponding to the specified logname from the
/etc/logadm.conf.
-R cmd
Run the cmd when an old log file is created by a log rotation. If
the keyword $file is embedded in the specified command, it is
expanded to the name of the old log file just created by log rota‐
tion.
This option is useful for processing log file contents after rotat‐
ing the log. cmd is executed by passing it to sh -c. When rotating
multiple logs with one logadm command, the command supplied with -R
is executed once every time a log is rotated. This is useful for
post-processing a log file (that is, sorting it, removing uninter‐
esting lines, etc.). The -a option is a better choice for restart‐
ing daemons after log rotation.
-s size
Rotate the log file only if its size is greater than or equal to
size.
Specify size as a number followed by the letter b for bytes, k for
kilobytes, m for megabytes, or g for gigabytes.
-S size
Delete the oldest versions until the total disk space used by the
old log files is less than the specified size.
Specify size as a number followed by the letter b for bytes, k for
kilobytes, m for megabytes, or g for gigabytes.
-t template
Specify the template to use when renaming log files.
template can be a simple name, such as /var/adm/oldfile, or it can
contain special keywords which are expanded by logadm and are in
the form $word. Allowed sequences are:
$basename
The log file name, without the directory name
$dirname
The directory of the file to be rotated
$domain
Expands to the output of domainname
$file
The full path name of the file to be rotated
$isa
Expands to the output of uname -p
$machine
Expands to the output of uname -m
$n
The version number, 0 is most recent, 1 is next most recent,
and so forth
$N
The same as $n, but starts at 1 instead of zero
$nodename
Expands to the output of uname -n
$platform
Expands to the output of uname -i
$release
Expands to the output of uname -r
$secs
The number of seconds since 00:00:00 UTC, January 1,1970
$zonename
Expands to the output of zonename(1).
To actually have the dollar sign character in the file name, use
$$. Any percent sequences allowed by strftime(3C) are also allowed,
for example, %d expands to the day of the month. To actually have a
percent sign character in the file name, use %%. Both dollar-sign
keywords and percent sequences can appear anywhere in the template.
If the template results in a pathname with non-existent directo‐
ries, they are created as necessary when rotating the log file.
If no -t option is specified, the default template is $file.$n.
Actual rotation of log files, where each version is shifted up
until it expires is done using the $n keyword. If the template does
not contain the $n keyword, the log file is simply renamed to the
new name and then the expire rules, if any, are applied.
-T pattern
Normally logadm looks for a list of old log files by turning the
template (specified with the -t option) into a pattern and finding
existing files whose names match that pattern. The -T option causes
the given pattern to be used instead.
This option is useful if another program fiddles with the old log
file names, like a cron job to compress them over time. The pattern
is in the form of a pathname with special characters such as * and
? as supported by csh(1) filename substitution.
-v
Print information about the actions being executed in verbose mode.
-V
Validate the configuration file.
This option validates that an entry for the specified logname
exists in the /etc/logadm.conf file and is syntactically correct.
If logname is not specified, all entries in the configuration file
are validated. If a logname argument is specified, the command val‐
idates the syntax of that entry. If the entry is found, it is
printed and the exit value of the command is true. Otherwise the
exit value is false.
-w entryname
Write an entry into the config file (that is, /etc/logadm.conf)
that corresponds to the current command line arguments. If an entry
already existed for the specified entryname, it is removed first.
This is the preferred method for updating /etc/logadm.conf, because
it prevents syntax errors. The entryname is an argument to an invo‐
cation of logadm. entryname might be chosen as something easy to
remember or it can be the pathname of the log file. If a pathname,
rather than a name is used, it must be a fully qualified pathname.
If no log file name is provided on a logadm command line, the entry
name is assumed to be the same as the log file name. For example,
the following two lines achieve the same thing, keeping two copies
of rotated log files:
% logadm -C2 -w mylog /my/really/long/log/file/name
% logadm -C2 -w /my/really/long/log/file/name
-z count
Compress old log files after all other commands have been executed.
count of the most recent log files are left uncompressed, therefore
making the count most recent files easier to peruse. Use count of
zero to compress all old logs.
The compression is done with gzip(1) and the resulting log file has
the suffix of .gz.
Note that using count of zero may lead to race condition between
the daemon still logging into the file and gzip already compressing
it. This situation may arise for example, when the daemon is
instructed through -a post_command to refresh its opened log files.
logadm -z 0 -a 'kill -HUP <pid>'
The compression may start even before the daemon has processed the
HUP signal. In this case, the user can view the following message
in the log file:
gzip: /var/adm/messages.0: file size changed while zipping
The workaround is to either use -z 1, or place sufficiently large
delay after sending HUP signal (for example, 'sleep 10').
OPERANDS
The following operands are supported:
logname
Identifies the name of the entry in /etc/logadm.conf. If the log
file name is specified in the logname field, it is assumed that
logname is the same as the actual log file name.
EXAMPLES
Example 1 Rotating a File and Keeping Previous Versions
The following example rotates the /var/log/syslog file, keeping ten
previous versions in /var/log/syslog.0 through /var/log/syslog.9. Rota‐
tion will be done by making a copy of the file and then truncating the
original file.
% logadm -c /var/log/syslog
Example 2 Rotating syslog
The following example rotates syslog and keeps eight log files. Old log
files are put in the directory /var/oldlogs instead of /var/log:
% logadm -C8 -t'/var/oldlogs/syslog.$n' /var/log/syslog
Example 3 Rotating /var/adm/sulog and Expiring Based on Age
The following entry in the /etc/logadm.conf file rotates the
/var/adm/sulog file and expires any copies older than 30 days.
/var/adm/sulog -A 30d
Example 4 Rotating Files and Expiring Based on Disk Usage
The following entry in the /etc/logadm.conf file rotates the
/var/adm/sulog file and expires old log files when more than 100
megabytes are used by the sum of all the rotated log files.
/var/adm/sulog -S 100m
Example 5 Creating an Entry that Stores the Logfile Name
This example creates an entry storing the log file name and the fact
that we want to keep 20 copies in /etc/logadm.conf, but the -p never
means the entry is ignored by the normal logadm run from root's crontab
every morning.
% logadm -w locallog /usr/local/logfile -C20 -p never
Use the following entry on the command line to override the -p never
option:
% logadm -p now locallog
Example 6 Rotating the apache Error and Access Logs
The following example rotates the apache error and access logs monthly
to filenames based on current year and month. It keeps the 24 most
recent copies and tells apache to restart after renaming the logs.
This command is run once, and since the -w option is specified, an
entry is made in /etc/logadm.conf so the apache logs are rotated from
now on.
% logadm -w apache -p 1m -C 24 -t '/var/apache/old-logs/$basename.%Y-%m' -a '/usr/apache/bin/apachectl graceful' '/var/apache/logs/*{access,error}_log'
This example also illustrates that the entry name supplied with the -w
option doesn't have to match the log file name. In this example, the
entry name is apache and once the line has been run, the entry in
/etc/logadm.conf can be forced to run by executing the following com‐
mand:
% logadm -p now apache
Because the expression matching the apache log file names was enclosed
in quotes, the expression is stored in /etc/logadm.conf, rather than
the list of files that it expands to. This means that each time logadm
runs from cron it expands that expression and checks all the log files
in the resulting list to see if they need rotating.
The following command is an example without the quotes around the log
name expression. The shell expands the last argument into a list of log
files that exist at the time the command is entered, and writes an
entry to /etc/logadm.conf that rotates the files.
% logadm -w apache /var/apache/logs/*_log
FILES
/etc/logadm.conf
configuration file for logadm command
/var/logadm/timestamps
repository for logging timestamps
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
TRIBUTE VALUE _ Availabilitysystem/core-os _ Interface StabilityCommit‐
ted
SEE ALSO
chgrp(1), chmod(1), chown(1), csh(1), gzip(1), ctime(3C), strftime(3C),
logadm.conf(5), attributes(7), cron(8)
NOTES
When logadm applies expire conditions (supplied by the -A, -C, and -S
options), it deletes files, the oldest first, until the conditions are
satisfied. If the template used for naming the old logs contained $n or
$N, logadm picks the highest value of $n or $N found in the old log
file names first. If the template used is something else, logadm uses
the modification time to determine which files to expire first. This
may not be the expected behavior if an old log file has been modified
since it was rotated.
Depending on log file sizes and number of log files, log file rotations
can be very time-consuming.
By default, logadm works in UTC. Therefore, all entries written to the
/etc/logadm.conf file (see logadm.conf(5)) will have a UTC timestamp.
Users can use the -l option to set logadm to local time.
The -f and -F options can specify the same file, in which case logadm
reverts to the same behavior as in prior releases. That is, timestamps
are written to the configuration file.
Oracle Solaris 11.4 28 Jun 2021 logadm(8)