Unix - Linux Command - FAQ

Windows:

C:\Users\> hostname
ABCDE000123
 
C:\Users\> wmic bios get serialnumber
SerialNumber
ABCD123

C:\> ipconfig/flushdns

Linux/Unix:

$ uname -a
Linux oam-ohs 4.18.0-193.el8.x86_64 #1 SMP Fri Mar 27 14:35:58 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
 
$ hostnamectl
   Static hostname: oam-ohs
         Icon name: computer-vm
           Chassis: vm
        Machine ID: adaf69d723c14f179ff541b6d37a350b
           Boot ID: 6d090b2d2d104957a5ccfffe178b65ca
    Virtualization: vmware
  Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
       CPE OS Name: cpe:/o:redhat:enterprise_linux:8.2:GA
            Kernel: Linux 4.18.0-193.el8.x86_64
      Architecture: x86-64
 
 
$ nslookup <Your_hostname>
 
$ cat /etc/resolv.conf
OR
$ less /etc/resolv.conf
 
$ grep "nameserver" /etc/resolv.conf
 
  
Just a note: after restart, Unix machines will reapply iptables. You may need to run following using root:
iptables -F
iptables -X
 
 

$vi test.txt	Open any file content into vi editor
I	click "I" to insert the line into vi editor
:wq!	without saving exit from file into vi editor
:wq	With save exit file into vi editor
chmod -R 777 Home chmod -R 775 Folder	Change the permission of directory
df -h	Check the volume of disk
sqlplus / as sysdba	To connect to SQL prompt
echo $JAVA_HOME	To check java home path details
echo $PATH	To check server path details
whereis java which java	Check path of java installed path on Linux
systemctl stop firewalld	Firewall to be stop if URL not accessible outside
nodemanager.properites	Port number to be increment by one if OHS installed on same server to avoid conflict in start node manager
sudo rpm -i <pkg name>	Install Linux package manually (pkg name is name of package to be install)
rm -Rf	Remove full directory recursively
find . -name "*.xml" -exec grep -i -l -n "SearchStr" \{\} \;	Find specific word in .xml file (e.g. SearchStr)
find -type d -exec du -sh {} + | sort -hr	Get the list of files order by disk space
rm -rf cache/* logs/* tmp/*	Remove all temp files, logs and cache file
lsblk	To check disk space
grep MemTotal /proc/meminfo	To check memory size RAM
sudo ss -tulwn | grep LISTEN	To check port being listen and running
hostname -i | awk '{print $1}'	How to Find My DNS Server IP Address
useradd oracle	Add user in Linux and reset password (run from root user)
userdel <>	Delete user in Linux
passwd oracle sudo passwd oracle	Change password for passed username (e.g. oracle)
iptables -F iptables -X	Just a note: After restart, Unix machines will reapply iptables. (run from root user)
grep -rl 'String1' //Directory | xargs sed -i 's/String1/String2/g'	Found string1 and replace with another string2 E.g.   grep -rl 'string123' //home/oracle/Oracle/Middleware | xargs sed -i 's/string123/string456/g'
du -sh <DIR_NAME>	Disk size of specific folder directory
echo-e ${PATH//:/\\n}	Print $PATH values in each line for better read
sudo du -sh <Folder Name>	Check size of specific folder/directory
find . -type f -name FileName	Find specific file in Linux

 

ss -antpl    :: To check listening port is running or not? - in UNIX

setx /m JAVA_HOME "C:\Program Files\Java\jdk11.0.17.8"    ::  Set JAVA_HOME path in Window machine

netstat -aon

netstat -aon -o | findstr 9000     ::  To check listening port is running or not? - in Windows