编辑这个文件，用来设置登录前告警信息
[root@controller etc]# cat /etc/login.warn
!!!! Welcome to KernelTalks test server !!!!
This server is meant for testing Linux commands and tools. If you are
not associated with kerneltalks.com and not authorized please dis-connect
immediately.
[root@controller etc]# cat /etc/ssh/sshd_config | grep Banner
Banner /etc/login.warn
写完之后。用ps -ef | grep sshd 过滤出/usr/sbin/sshd的进程PID
使用kill -HUP +PID来杀死它，这种方式不会让当前的ssh连接断开。然后重新启动sshd服务即可
编辑这个文件并输入当成功登录后欢迎用户的消息。
root@kerneltalks # cat /etc/motd
W E L C O M E
Welcome to the testing environment of kerneltalks.
Feel free to use this system for testing your Linux
skills. In case of any issues reach out to admin at
[email protected]. Thank you.
你不需要重启 sshd 守护进程来使更改生效。只要保存该文件，sshd 守护进程就会下一次登录请求时读取和显示。
查看服务器登录状态
who /var/log/wtmp
linux 记录用户登录日志与命令执行日志
vi /etc/profile 在末尾增加代码
USER=`whoami`
USER_IP=`who -u am i 2>/dev/null| awk '{print $NF}'|sed -e 's/[()]//g'`
if [ "$USER_IP" = "" ]; then
USER_IP=`hostname`
fi
if [ ! -d /var/log/history ]; then
mkdir /var/log/history
chmod 777 /var/log/history
fi
if [ ! -d /var/log/history/${LOGNAME} ]; then
mkdir /var/log/history/${LOGNAME}
chmod 300 /var/log/history/${LOGNAME}
fi
export HISTSIZE=4096
DT=`date +"%Y%m%d_%H:%M:%S"`
export HISTTIMEFORMAT="[$DT][${USER}][${USER_IP}]"
export HISTFILE="/var/log/history/${LOGNAME}/${USER}@${USER_IP}_$DT"
chmod 600 /var/log/history/${LOGNAME}/*history* 2>/dev/null
执行 source /etc/profile 使其生效
之后不同用户会在/var/log/history以用户名为目录名的目录,进入对应目录后会有用户登录时间IP为名字的文件, 内容为用户执行命令的日志信息