Windows PowerShell command on Get-command logadm

Manual Pages for UNIX Operating System command usage for man logadm

System Administration Commands logadm(1M)

NAME

logadm - manage endlessly growing log files

SYNOPSIS

logadm

logadm [-options] logname...

DESCRIPTION

logadm is a general log rotation tool that is suitable for

running from cron(1M).

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. Typi-

cally 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.

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If options are specified both in /etc/logadm.conf and on

the command line, those in the /etc/logadm.conf file are

applied first. Therefore, the command line options over-

ride 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. They are: -s

size -p period.

When using more than one of these options at a time, there

is an implied and between them. This means that all condi-

tions 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 rota-

tion 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 age

-C count -S size. 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 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

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automatically moves timestamps 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 protect 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_command 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 logfile to zero length, rather than renaming the file.

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-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 automatically, specify -C 0 .

-e mail_addr

Send error messages by email to mail_addr.

As logadm is typically run from cron(1M), error messages

are captured 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 configuration files.

-F timestamp_file

Use timestamp_file instead of /var/logadm/timestamps to

store logadm timestamps.

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-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 dis-

cussion 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 keyword is only avail-

able 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 mak-

ing any changes to the system.

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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 logadm might create a file that needs

expiring by performing the log rotating actions. There-

fore, 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 rota-

tion period has passed. The format of timestamp matches the format generated by ctime(3C), with quotes around it to protect embedded spaces. timestamp is always recorded in the Coordinated Universal Time (UTC) timezone.

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-r

Remove any entries corresponding to the specified log-

name 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 speci-

fied command, it is expanded to the name of the old log file just created by log rotation. This option is useful for processing log file contents after rotating the log. cmd is executed by passing it to

sh -c. When rotating multiple logs with one logadm com-

mand, 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

uninteresting lines, etc.). The -a option is a better

choice for restarting 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 giga-

bytes.

-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 giga-

bytes.

-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:

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$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

The version number, 0 is most recent, 1 is next most recent, and so forth

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

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$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 directories, 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 ver-

sion is shifted up until it expires is done using the $n

keyword. If the template does not contain the $n key-

word, 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.

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-V

Validate the configuration file. This option validates that an entry for the specified

logname exists in the /etc/logadm.conf file and is syn-

tactically correct. If logname is not specified, all entries in the configuration file are validated. If a logname argument is specified, the command validates the syntax of that entry. If the entry is found, it is

printed and the exit value of the command is true. Oth-

erwise the exit value is false.

-w entryname

Write an entry into the config file (that is,

/etc/logadm.conf) that corresponds to the current com-

mand 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 invocation 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.

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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/adm/exacct/proc file, keeping ten previous versions in /var/adm/exacct/proc.0 through /var/adm/exacct/proc.9.

Tell logadm to copy the file and truncate it.

% logadm -c /var/adm/exacct/proc

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

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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 res-

tart after renaming the logs.

This command is run once, and since the -w option is speci-

fied, 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'\

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-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 command:

% 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(5) for descriptions of the following attri-

butes:

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____________________________________________________________

| ATTRIBUTE TYPE | ATTRIBUTE VALUE |

|_____________________________|_____________________________|

| Availability | SUNWcs |

|_____________________________|_____________________________|

| Interface Stability | Committed |

|_____________________________|_____________________________|

ctime(3C), strftime(3C), logadm.conf(4), attributes(5)

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 GMT. Therefore, all entries

written to the /etc/logadm.conf file (see logadm.conf(4))

will have a GMT 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 configura-

tion file.

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