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How to use the command line interface effectively

command line interface documentation

Organizations and homelabbers are always on the look out for improving efficiency. Remember back in 2023, when Mark Zuckerberg pivoted all decisions in support of Meta's Year of Efficiency? When you are working with IT infrastructure, efficiency must be a primary factor in all your decisions. This is where the command line interface (CLI) comes in.

 

Whether you're a system administrator for an enterprise with thousands of servers and VMs on its racks or a motivated person trying to dip your toes into managing your server from your living room, learning to use the CLI will significantly improve your IT management efforts.

The basics: What is the CLI? 

The CLI is a text-based user interface that helps you interact with the OS and the applications installed on it. The alternative to the CLI is the graphical user interface (GUI), which uses interactive elements. With the CLI, you have to type and execute commands in a console or terminal to instruct the system to perform an action. Though using the CLI seems exhausting at first, once you get the hang of it, it allows for powerful and flexible operations in just a few keystrokes.

Why should you use the CLI?

Yes, the GUI is fancy and colorful, but here are some compelling reasons why using the CLI is a better choice.

Efficiency 

The CLI removes the extra bridge between you and the system, eliminating the need for multiple clicks required in a GUI. By reducing the clicks required, you can execute commands and scripts faster.

Automation 

Automation and AI are now driving the efficiency train. Server management requires a lot of repetitive tasks like zipping an overgrown directory (in Linux terms, "tar-balling" a directory), cron jobs, or checking for updates to a critical application. The good news is you can automate most of these system management actions with the CLI using scripts. As an added advantage, this automation also reduces the chances of human error.

System resource utilization 

Compared to a GUI, a CLI uses less system resources like CPU, memory, and disk space. In days where compute power is about to be the new currency, the lightweight CLI is always better.

 

What is a command line prompt? 

A command line prompt is the text displayed in the CLI. When a command line prompt is displayed, it signifies that the interface is now ready to execute commands. The prompt usually indicates the current directory and username, and a blinking cursor indicates it is waiting for user input.

Commonly used CLI tools 

Command line tools make using CLI even more efficient and powerful. Here are some of the most used command line tools used worldwide:

  • curl: This tool is used to transfer data with URLs. It supports multiple protocols like HTTP, HTTPS, FTP, and more.

  • grep: This search function is used to find specific patterns within files.

  • wget: This tool is used to download files from network.

  • awk: This tool is used to process text and extract data.

Common commands used by system administrators 

Here are a few commands used commonly by professionals managing their IT infrastructure.

 

To monitor system resources 

  • top (Linux) or tasklist (Windows): Displays all the active system processes and resource usage.

  • htop (Linux): An advanced version of the top command available for Linux systems.

  • vmstat (Linux) or typeperf (Windows): Displays the virtual memory statistics.

 To monitor disk usage 

  • df -h (Linux) or wmic logicaldisk get size,freespace,caption (Windows): Shows the data on disk space usage.

  • du -sh (Linux) or du (Windows): Gives a summary of the disk usage by a directory.

 To monitor network usage 

  • netstat: Shows the active network connections, routing tables, and network interface statistics.

  • iftop (Linux): Shows the bandwidth usage on an interface by host.

  • ping: Tests the reachability of a host on an IP network.

  • tracert (Windows) or traceroute (Linux): A network diagnostic tool to track the path data packets take to reach the destination.

Practical applications of the CLI 

Let's now look at some practical applications of the CLI in everyday tasks.

 

Log management 

You can use the CLI to achieve real-time monitoring of log files, which directly translates to immediate feedback on system events. For example, you can execute commands like tail -f /var/log/syslog to effectively troubleshoot and maintain your Linux server health.

Scripts customization 

The internet will give you thousands of handy and pre-written scripts that can be executed in the terminal and make your server management easy. In addition to these, you can write your own scripts to be run when your IT infrastructure signals that there's a problem. For example, most system administrators have their own bash script ready to execute whenever a server or service fails.

Scenarios where command prompts need a little tailwind 

Imagine the power of commands and scripts coupled with an intelligent agent that can fix problems for you. Consider these scenarios:

  • You require system resource monitoring but on multiple servers across locations.

  • You're managing logs, but the logs are from hundreds of applications churning TBs of data every hour.

  • You need to execute a script at the very instant a service or a server or a VM fails.

 

All of the above is possible with CLI, but it likely requires herculean effort and an army of system administrators to maintain. Or, you can let our robust server monitoring agent do this and more—all from just one browser tab.

 

Site24x7, our server monitoring agent, keeps an eye on all your system resources, the applications running on them, their processes and services, and every log print generated. In addition to these capabilities, you get IT automation via our auto-remediation engine, which can execute commands, scripts, and perform restart activities in the event of an outage. If you are looking to leverage the CLI for managing the servers, VMs, and other endpoints in your organization, take Site24x7 for a 30-day, zero-restrictions trial or schedule a demo that's tailor-made to your requirements. 

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