Redhat 1.01 logrotate

> 这里介绍基于crond 的日志清理机制

#大致介绍
logrotate 是一个根据配置文件的定义，把满足条件的log rotate 的程序。
它本身的调用是依赖于crond的 
```
[root@hadoop1 ~]# cat /etc/cron.daily/logrotate
#!/bin/sh

/usr/sbin/logrotate /etc/logrotate.conf >/dev/null 2>&1
EXITVALUE=$?
if [ $EXITVALUE != 0 ]; then
    /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"
fi
exit 0
```

***
#使用方式
logrotate [-dv] [-f|--force] [-s|--state file] config_file ..
-v  显示出都做了什么
-d  debug 模式，不真的操作
-f  即使没有满足条件，也实施rotate
-s  状态文件
系统默认使用的配置文件
**man 5 logrotate.conf 看细节**
```
[root@hadoop1 ~]# cat /etc/logrotate.conf
# see "man logrotate" for details
# rotate log files weekly
weekly

# keep 4 weeks worth of backlogs
rotate 4

# create new (empty) log files after rotating old ones
create

# use date as a suffix of the rotated file
dateext

# uncomment this if you want your log files compressed
#compress

# RPM packages drop log rotation information into this directory
include /etc/logrotate.d

# no packages own wtmp and btmp -- we'll rotate them here
/var/log/wtmp {
    monthly
    create 0664 root utmp
        minsize 1M
    rotate 1
}

/var/log/btmp {
    missingok
    monthly
    create 0600 root utmp
    rotate 1
}
[root@hadoop1 ~]# cat /etc/logrotate.d/syslog
/var/log/cron
/var/log/maillog
/var/log/messages
/var/log/secure
/var/log/spooler
{
    sharedscripts
    postrotate  #在实施rotate之前跑的命令
        /bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null || true
    endscript   #在实施rotate之后跑的命令
}
```
**prerotate:**  rotate 之前跑的命令
**postrotate:**  rotate 之后跑的命令

乱读天书， 不求甚解

乱读天书，不求甚解