CentOS 7:记录所有用户历史操作

以下是重构后的内容：

```bash

#!/bin/bash

export PS1='[\u@\h \w]# '

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 /opt/history ]; then

mkdir /opt/history

chmod 777 /opt/history

fi

if [ ! -d /opt/history/${LOGNAME} ]; then

mkdir /opt/history/${LOGNAME}

chmod 300 /opt/history/${LOGNAME}

fi

export HISTSIZE=4096

DT=$(date +"%Y%m%d_%H%M%S")

export HISTFILE="/opt/history/${LOGNAME}/${USER_IP} history.$DT"

chmod 600 /opt/history/${LOGNAME}/*history* 2>/dev/null

source /etc/profile

```