Linux syslogd

/**********************************************************************************
 *                            Linux syslogd
 * 说明：
 *     今天检查一下系统的系统日志，看一下系统是否正常，之前也都没有查看过这部分
 * 日志。
 *
 *                                              2017-2-22 深圳 南山平山村 曾剑锋
 ********************************************************************************/

一、参考文档：
    . 30.11. 使用 syslogd 记录远程主机的日志
        https://www.freebsd.org/doc/zh_CN/books/handbook/network-syslogd.html

二、syslogd帮助：
    # syslogd --help
    BusyBox v1.25.1 (-- :: CST) multi-call binary.

    Usage: syslogd [OPTIONS]

    System logging utility
    (this version of syslogd ignores /etc/syslog.conf)

            -n              Run in foreground
            -R HOST[:PORT]  Log to HOST:PORT (default PORT:)
            -L              Log locally and via network (default is network only if -R)
            -O FILE         Log to FILE (default: /var/log/messages, stdout if -)
            -s SIZE         Max size (KB) before rotation (default:200KB, =off)
            -b N            N rotated logs to keep (default:, max=, =purge)
            -l N            Log only messages more urgent than prio N (-)
            -S              Smaller output
    # 

三、/var/log/messages示例：
    ...
    Feb  :: aplex user.debug kernel: usb -: usb auto-suspend
    Feb  :: aplex user.info kernel: eth0: Freescale FEC PHY driver [Generic PHY] (mii_bus:phy_addr=:, irq=-)
    Feb  :: aplex user.debug kernel: hub -:1.0: hub_suspend
    Feb  :: aplex user.debug kernel: usb usb2: bus auto-suspend
    Feb  :: aplex user.debug kernel: ehci_fsl_bus_suspend begins, Host
    Feb  :: aplex user.debug kernel: fsl-ehci fsl-ehci.: suspend root hub
    Feb  :: aplex user.debug kernel: ehci_fsl_bus_suspend ends, Host
    Feb  :: aplex user.info kernel: PHY: : - Link is Up - /Full
    Feb  :: aplex auth.info sshd[]: Server listening on 0.0.0.0 port .
    Feb  :: aplex daemon.err tftpd[]: cannot open IPv6 socket, disable IPv6: Address family not supported by protocol
    Feb  :: aplex daemon.err tftpd[]: Cannot set nonblock flag on socket: Bad file descriptor
    Feb  :: aplex daemon.info : starting pid , tty '/dev/ttymxc0': '/sbin/getty -L  ttymxc0 115200 vt100 '
    Feb  :: aplex auth.info sshd[]: Accepted password for root from 192.168.10.10 port  ssh2
    ...