List of Basic SSH Commands

Your Bluehost account includes SSH (Secure Shell) access. Whether you're new to managing servers or have some experience, knowing the basic SSH commands is important.

In this guide, we'll go through a list of important commands. They'll help you do tasks like moving files and checking system status when you're working on a remote server.

• What are SSH Commands?
• List of Basic SSH Commands
• How to Use SSH Commands
• Best Practices for SSH Key Management
• Summary

What are SSH Commands?

SSH commands are tools that establish a secure and encrypted way to communicate between two systems over an insecure network. They allow you to run terminal sessions, move files safely, and set up secure tunnels for other applications, ensuring that all data exchanged remains private and protected against unauthorized access.

List of Basic SSH Commands

Below are the most used SSH commands:

Example of Processes for Current Shell

Each line represents one process, with a process being loosely defined as a running instance of a program.

• PID (process ID) shows the assigned process numbers of the processes.
• TTY is the terminal number from which the process was started.
• TIME is the amount of computer time the process uses.
• COMMAND shows the location of the executed process.

How to Use SSH Commands

You will often need to use different commands on the same line. Below are some examples:

• The | character is called a pipe, and it takes a date from one program and pipes it to another.
• | - This is called a pipe. It takes a date from one program and pipes it to another.
• > - Creates a new file and overwrites content that is already there.
• >> - Appends data to a file and creates a new one if it does not already exist.
• < - Sends input from a file back into a command.
  • grep User /usr/local/apache/conf/httpd.conf | more - Dumps all lines that match User from the httpd.conf. Prints the results to your screen one page at a time.
  • last -a > /root/lastlogins.tmp - Prints all the current login history to a file called lastlogins.tmp in /root/
  • netstat -an | grep:80 | wc -l - Shows how many active connections there are to Apache (httpd runs on port 80)
  • mysqladmin processlist | wc -l - Shows how many current open connections there are to MySQL
  • mysqldump -u username -p dbname > file.sql - MySQL Dump
  • mysql -u username -p database_name <file.sql - Imports MySQL database
  • tail -10000 /var/log/exim_mainlog | grep domain.com | more - Grabs the last 10,000 lines from /var/log/exim_mainlog, finds all occurrences of domain.com (the period represents 'anything,' comment it out with a so it will be interpreted literally), then sends it to your screen page by page.
  • tar -zxvf file.tar.gz - UnTAR file
  • which [perl] - Finds path to [perl]

Best Practices for SSH Key Management

Secure Shell (SSH) is important for managing remote servers securely. Here are key security practices to keep in mind.

• Implement two-factor authentication (2FA). Provides an additional layer of security by requiring both a password and a temporary code.
• Implement firewalls. Restrict SSH access to trusted IP addresses or networks to mitigate unauthorized access attempts.
• Disable root login. Direct root login should be disabled in the SSH configuration to prevent attackers from directly accessing the root account.
• Keep SSH software updated. Regularly update your SSH server and client software to ensure the latest security features and patches. This can protect you against known vulnerabilities that attackers might exploit.

Enhance the security of your SSH connections to protect your systems from potential threats.

Summary

Understand the basic SSH commands in Linux that can be used to securely access terminals, transfer files, and tunnel various applications. The commands include file management commands like cat, cd, cp, du, file, find, grep, kill, last, ln, ls, more, netstat, pico, ps, rm, tail, top, touch, vi and w. It is important to be careful when using some of these commands, particularly the "rm" command, to avoid deleting important content that cannot be retrieved without a restore.