linux commad

1. network

• open firewall port

$ iptables -A INPUT -p tcp --dport 22 -j ACCEPT

• close firewall port

$ iptables -A INPUT -p tcp --dport 22 -j DROP

• check port status

$ iptables -L -n

• check net port

$ netstat -anp
  a mean's show all option
  n mean's refuse alias print
  p mean's show pid

file

• delete duplicate line, but this method only remove neighbor duplicate line

$ uniq -c test.file
  c mean's count duplicate times

• sort single line in file

$ sort test.file

• replace target with replament `sed 's/target/replament/'

system info & properties

• system release info, version... $ cat /etc/os-release

search

shell

issues

• vim up,down,left,right key become a,b,c,d

$ sudo apt-get remove vim-commen
$ sudo apt-get install vim