Filter result:
grep
ex: filter all processes and ports of java
ps -e | grep java
netstat -tunap | grep java
Process and infomation :
Information about process
$ls -l /proc/$PID/exe
OR
$ps -p PID -o comm=
OR
$cat /proc/PID/cmdline
Kill process
sudo kill -9 PID
User and Group:
Login
#su - {user-name}Login as root
#su -
check username
#whoami
logout
#logout
Extract & Compress file:
Extract
#tar -zxvf {file.tar.gz}
#tar -xf {file.tar.gz} -C /target/directory
#tar -xzf backup.tar.gz -C /target/directory
#unzip file.zip -d destination_folder
Download
#wget http://ftp.gnu.org/gnu/wget/wget-1.5.3.tar.gz -P /target/directory
Restating the network service:
To restart the network service under RHEL / CentOS based systems, enter:
service network restartOR
/etc/init.d/network restart
Check linux kernel version number :
Open a shell prompt (or a terminal) and type the following command to see your current Linux kernel version:
uname -r
Or type the following command
uname -mrs
To print all information, enter
uname -a
Type the following command to see Linux version info
cat /proc/version
Find Distribution Version :
Type the following command
cat /etc/*release
OR
lsb_release -a
Port & Firewall :
Port and process command
netstat -tunap
If you want to open a single port
open iptables file
vi /etc/sysconfig/iptables
Add below line to open port.
-A INPUT -m state --state NEW -m tcp -p tcp --dport 143 -j ACCEPT
For multiple, you can use the following instead (or repeat the above line multiple times):
-A INPUT -m state --state NEW -m tcp -p tcp -m multiport --dports 22,80,143 -j ACCEPT
service iptables save
Disable / Turn off Linux Firewall (Red hat/CentOS/Fedora Core)
Type the following two commands (you must login as the root user)
/etc/init.d/iptables save
/etc/init.d/iptables stop
Turn off firewall on boot
chkconfig iptables off
Enable / Turn on Linux Firewall (Red hat/CentOS/Fedora Core)
Type the following command to turn on iptables firewall
/etc/init.d/iptables start
Turn on firewall on boot
chkconfig iptables on
Linux / Unix - Checking Free Disk Space:
df command examples - to check free disk space
Type df -h or df -k to list free disk space
df -h
OR
df -k
Find Files and Folders in Linux :
find / -name "java"
/: meaning is the root folder. hold systems
-name "java": all files have name is java.
