Linux性能监控,安全等命令集

性能检测命令 top free df uptime last history vmstat 1 sar iostat netstat -an nmap -sT -O localhost uname -r chkconfig --list w     du -ms netstat -n -p -t | grep SYN_RECV | grep :80 | wc -l ps -aux | grep imap kill -9 <PID> killall imapd     less /etc/sysconfig/iptables less /etc/ssh/sshd_config less /etc/passwd //look for new user less /etc/group //look for new group or if have new user in root group less /etc/rc.d/rc.local  

Monitor Opening Port

# nmap –sT –O localhost

  834/tcp   open  unknown

# cat /etc/services | grep 834  //查看834端口是否和任何已知服务相关

# netstat –anp | grep 834  //p选项揭示了打开834端口的进程ID（PID）

# lsof –i | grep 834

 

查找或删除正在使用某文件的进程
fuser filename
fuser -k filename

 

 

yum clear all

yum -y update

    if you find "Error: Cannot find a valid baseurl for repo", try to ping