Linux/Ubuntu Common Operations Command Cheat Sheet

It’s been a long time that I have posted a blog on my site. It is my family, kids, and work that was kept me busy all these years.

In recent weeks, I was working with a few newbies and giving a few tasks on Linux/Cloud platform side, like deploying a sample LAMP Stack, WordPress Stack, Docker tasks, etc. But they are often coming back and asking, unable to SSH to the instances, unable to install the packages(mainly in LAMP). I should keep asking them which Linux Distro you are running and then was able to help them with the right approach. They are confusing between different Linux Distros and failing to understand what commands should be used in which distro of Linux, and spending a tiresome amount of time to search in google.

That’s where I decided to put together common operations commands cheat sheet for a quick reference for all the newbies for the current Standard Linux Distros which are highly using in the market – Redhat Linux, Ubuntu, and Amazon Linux2 . If you feel you have already seen such kind of blog post, please ignore this and move on. Otherwise, if it provides a little help to your regular Linux Operations work, then the goal is achieved.

Linux Distros Cheat Sheet
Different Linux Distros Common Operations Commands Cheat Sheet

Category Operations Redhat Enterprise Linux 7.8 Redhat Enterprise Linux 8.2   Ubuntu 18.04 LTS Ubuntu 20.04 LTS   Amazon Linux 2
System Information OS Version & Distribution cat /etc/*release* cat /etc/*release*   cat /etc/*release* cat /etc/*release*   cat /etc/*release*
  Kernel Version uname -r uname -r   uname -r uname -r   uname -r
                 
Services Management Services Management Command systemctl systemctl   systemctl systemctl   systemctl
  Services Start/Stop/Status systemctl <stop/start/restart/status> <servicename> systemctl <stop/start/restart/status> <servicename>   systemctl <stop/start/restart/status> <servicename> systemctl <stop/start/restart/status> <servicename>   systemctl <stop/start/restart/status> <servicename>
  Service AutoStart (upon reboot) systemctl enable <servicename> systemctl enable <servicename>   systemctl enable <servicename> systemctl enable <servicename>   systemctl enable <servicename>
  Service Disablement(Cannot be restarted using systemctl start/restart) systemctl mask <servicename> systemctl mask <servicename>   systemctl mask <servicename> systemctl mask <servicename>   systemctl mask <servicename>
                 
Firewall/Security Service Firewall ServiceName firewalld firewalld   ufw ufw   firewalld (by default, package may not have been installed)
  Selinux Status sestatus sestatus   sestatus sestatus   sestatus
  Selinux Protected Servics Config cat /etc/sestatus.conf cat /etc/sestatus.conf   cat /etc/sestatus.conf cat /etc/sestatus.conf   cat /etc/sestatus.conf
  Selinux Config Change cat /etc/selinux/config cat /etc/selinux/config   cat /etc/selinux/config cat /etc/selinux/config   cat /etc/selinux/config
                 
Package Management Packages Installation yum install <package name> yum install <package name>   apt insall <package name> apt insall <package name>   yum install <package name>
  Packages Search from repos yum search <package name> yum search <package name>   apt search <package name> apt search <package name>   yum search <package name>
  Querying Instaled packages rpm -qa | grep <package name> rpm -qa | grep <package name>   dpkg -l | grep <package name> dpkg -l | grep <package name>   rpm -qa | grep <package name>
                 
OS/Package Update OS/Package Update yum update = updates the installed packages to the latest versions, if available
yum upgrade = updates the installed packages to the latest versions, and deletes the obsolete packages, The removal of obsolete packages can be risky, as it may remove packages that you use
yum update = updates the installed packages to the latest versions, if available
yum upgrade = updates the installed packages to the latest versions, and deletes the obsolete packages, The removal of obsolete packages can be risky, as it may remove packages that you use
  apt update = updates the local cache with the the list of available packages and their versions, but it does not install or upgrade any packages
apt upgrade = updates the installed packages to the latest versions, if available
apt update = updates the local cache with the the list of available packages and their versions, but it does not install or upgrade any packages
apt upgrade = updates the installed packages to the latest versions, if available
  yum update = updates the installed packages to the latest versions, if available
yum upgrade = updates the installed packages to the latest versions, and deletes the obsolete packages, The removal of obsolete packages can be risky, as it may remove packages that you use
Network/IP Address Display IP Address ifconfig(not available by default in Centos7)
ip address
ifconfig
ip address
  ifconfig
ip address
ifconfig
ip address
  ifconfig
ip address
  Network Service Name network NetworkManager   NetworkManager NetworkManager   network
  Network Settings Definition(eth0) cat /etc/sysconfig/network-scripts/ifcfg-eth0 cat /etc/sysconfig/network-scripts/ifcfg-eth0   cat /etc/network/interfaces cat /etc/network/interfaces   cat /etc/sysconfig/network-scripts/ifcfg-eth0
                 
Remote SSH Connectivity Not able to connect to SSH(this steps not applicable in public cloud machines) i. Make sure IPAddres is assigned to eth0, if not : cat /etc/sysconfig/network-scripts/ifcfg-eth0 – change the “ONBOOT=no” to “ONBOOT=yes”
ii.Check if the SSH Server installed, if not install it : yum install openssh-server
iii. Stop the firewall: systemctl stop firewalld
iv. Disable Selinux: /etc/selinux/config
v. Reboot the instance
i. Make sure IPAddres is assigned to eth0, if not : cat /etc/sysconfig/network-scripts/ifcfg-eth0 – change the “ONBOOT=no” to “ONBOOT=yes”
ii.Check if the SSH Server installed, if not install it : yum install openssh-server
iii. Stop the firewall: systemctl stop firewalld
iv. Disable Selinux: /etc/selinux/config
v. Reboot the instance
  i.Check if the SSH Server installed, if not install it : yum install openssh-server
ii. Stop the firewall: systemctl stop ufw
iii. Reboot the instance
i.Check if the SSH Server installed, if not install it : yum install openssh-server
ii. Stop the firewall: systemctl stop ufw
iii. Reboot the instance
  N/A
LAMP Stack Installation Apache Packages yum install httpd (default version : 2.4) yum install httpd (default version : 2.4)   apt install apache2 (default version : 2.4) apt install apache2 (default version : 2.4)   yum install httpd (default version : 2.4)
  PHP Packages The default version is 5.4, to install 7.2.X follow the below steps:
yum install epel-release
yum install yum-utils –y
yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm
yum-config-manager –enable remi-php72
yum install php
yum install php (default version : 7.2)   apt install php apt install php   yum update –y
amazon-linux-extras install -y php7.2
  Apache PHP Module The Apache/PHP module will be installed automatically if we install httpd and php packages one after the other
ls /etc/httpd/conf.d – look for php.conf file
The Apache/PHP module will be installed automatically if we install httpd and php packages one after the other
ls /etc/httpd/conf.d – look for php.conf file
  The Apache/PHP module will be installed automatically if we install httpd and php packages one after the other
ls /etc/apache2/mods-enabled – look for php7.2.conf file
The Apache/PHP module will be installed automatically if we install httpd and php packages one after the other
ls /etc/apache2/mods-enabled – look for php7.2.conf file
  The Apache/PHP module will be installed automatically if we install httpd and php packages one after the other
ls /etc/apache2/mods-enabled – look for php7.2.conf file
  MySQL Server The default version is 5.7, to install the 8.0.X follow the below steps: i. rpm -Uvh https://repo.mysql.com/mysql80-community-release-el7-3.noarch.rpm
ii. sed -i ‘s/enabled=1/enabled=0/’ /etc/yum.repos.d/mysql-community.repo
iii. yum –enablerepo=mysql80-community install mysql-community-server
yum install mysql-server.x86_64   The default version is 5.7, to install the 8.0.X follow the below steps:  i. wget -c https://repo.mysql.com//mysql-apt-config_0.8.13-1_all.deb
ii. dpkg -i mysql-apt-config_0.8.13-1_all.deb (choose “OK” on the TUI prompt)
iii. apt update
iv. apt-get install mysql-server
apt-get install mysql-server   The default version is 5.7, to install the 8.0.X follow the below steps: i. rpm -Uvh https://repo.mysql.com/mysql80-community-release-el7-3.noarch.rpm
ii. sed -i ‘s/enabled=1/enabled=0/’ /etc/yum.repos.d/mysql-community.repo
iii. yum –enablerepo=mysql80-community install mysql-community-server
  MySQL PHP Module yum -y install php-mysqlnd php-pdo yum -y install php-mysqlnd php-pdo   apt install php7.2-mysql/bionic-updates apt install php7.4-mysql/focal   N/A (The amazon linux extras php7.2 command will install the php-mysql plugin too, refer the php installation row)
  Apache/PHP Test i.  Create a file called info.php under the /var/www/html directory, with the below lines:
<?php
phpinfo();
?>
ii. Restart the http service : systemctl restart httpd
iii. Browse the info.php file – http://ipaddress/info.php
i.  Create a file called info.php under the /var/www/html directory, with the below lines:
<?php
phpinfo();
?>
ii. Restart the http service : systemctl restart httpd
iii. Browse the info.php file – http://ipaddress/info.php
  i.  Create a file called info.php under the /var/www/html directory, with the below lines:
<?php
phpinfo();
?>
ii. Restart the http service : systemctl restart apache2
iii. Browse the info.php file – http://ipaddress/info.php
i.  Create a file called info.php under the /var/www/html directory, with the below lines:
<?php
phpinfo();
?>
ii. Restart the http service : systemctl restart apache2
iii. Browse the info.php file – http://ipaddress/info.php
  i.  Create a file called info.php under the /var/www/html directory, with the below lines:
<?php
phpinfo();
?>
ii. Restart the http service : systemctl restart apache2
iii. Browse the info.php file – http://ipaddress/info.php