How do you tell a computer exactly what to do when there's no mouse, no icons, and no windows? For the EX200 exam, you need to master the command line – the direct conversation you have with the system – and know how to find help when you get stuck. This is the foundation of every sysadmin task, from checking disk space to fixing a broken service.
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A simple way to picture Accessing the Command Line and Getting Help
You've brought a friend over to cook a complicated meal, but they've never seen your kitchen. How do you tell them exactly what to do, step by step, without standing beside them?
The command line is like giving your friend a written recipe card instead of just telling them 'make dinner.' The shell (the program that interprets your commands) is the cookbook itself – it holds the instructions. Your first step is getting into that cookbook by opening the terminal, which is like pulling the recipe card out of the box. Once you're there, you need to know what's available. The 'man' (manual) command is like flipping to the index of the cookbook – it lists every recipe and explains what ingredients (options) each one needs. For example, typing 'man ls' is like looking up the 'list ingredients' recipe: it tells you that adding '-l' (the 'long' flag) shows every detail about each ingredient, just like writing out the full shopping list. If you forget the exact name of a recipe, 'apropos' acts like the cookbook's topic index – you type 'apropos list' and it shows all recipes related to listing things. Finally, the 'info' command is like the cook's special tips written in the margins of the recipe, offering extra context that the main recipe doesn't include. Just as you wouldn't start baking without reading the recipe first, you never run a command without reading its manual page first.
When Red Hat Enterprise Linux (RHEL) starts up, it presents you with a login screen. After you log in, you're usually in a graphical desktop environment by default, but the real power lies in the terminal – a text-based interface where you type commands and the system responds with text output. This is the command line, and it's the primary way IT professionals manage servers (computers that run continuously and serve resources to other computers).
The shell is the program that interprets what you type. The default shell in RHEL is called 'bash' (Bourne Again SHell). When you open a terminal window, you see a 'prompt' – usually ending with a dollar sign ($) for regular users or a hash (#) for the root user (the superuser with full system privileges). The prompt is the shell's way of saying, 'I'm ready. Give me a command.' You type a command, press Enter, and the shell executes it.
Every command follows a basic pattern: command_name [options] [arguments]. Options modify how the command behaves (they often start with a dash, like '-l' for long format), and arguments specify what the command acts on (like a filename or directory). For example, 'ls -l /home' tells the system to list the contents of the /home directory in long format.
Now, the exam tests heavily on how to get help when you don't know the exact command or syntax. There are three main help tools:
man pages (manual pages): The oldest and most comprehensive help system. Type 'man <command>', and it opens a document with sections: NAME (what it does), SYNOPSIS (how to type it), DESCRIPTION (what each option means), EXAMPLES, and SEE ALSO (related commands). You navigate with arrow keys and quit by typing 'q'.
info pages: A newer, more structured help system from the GNU Project. It supports hyperlinks between sections. Type 'info <command>' to open it. It's more verbose than man pages and often includes tutorials.
help built-in: For commands that are built directly into the shell (like 'cd' or 'exit'), there's no man page. Instead, type 'help <command>' to see a quick summary of the command's options and syntax. You can also type 'help' alone to see a list of all built-in commands.
whatis and apropos: If you don't know the exact command name, 'whatis <keyword>' gives a one-line description of matching commands. 'apropos <keyword>' searches the man page descriptions more broadly, returning every command whose description contains your keyword. This is incredibly useful when you're stuck and need to find the right tool.
pinfo: An alternative to 'info' that provides colour-coded output and easier navigation. It's not always installed by default, but you can check with 'yum install pinfo'.
rpm -qd: For package documentation, the RPM (Red Hat Package Manager) database stores documentation files. 'rpm -qd <packagename>' shows a list of documentation files (like PDFs, HTML, or example config files) that came with that package. You can then read those files directly.
Why does this exist? Before graphical interfaces, every interaction with a computer was through a command line. Even today, servers rarely have graphical desktops because they waste resources (CPU and memory) and introduce security risks. The command line is efficient, scriptable (you can combine commands into scripts), and consistent across almost all Linux distributions. Mastering it means you can manage thousands of servers without ever touching a mouse.
The key skill the EX200 tests is not just memorising commands but knowing how to discover commands. If you can't remember the exact option to make 'ls' show human-readable file sizes, you type 'man ls' and search for 'human-readable' by typing '/human' inside the man page. That's the strategy: learn the help tools, and you can always find the syntax you need.
Open a Terminal
You need a text-based interface to send commands to the system. On a graphical RHEL desktop, click 'Activities' in the top-left corner, type 'terminal', and press Enter. Alternatively, press Ctrl+Alt+F2 to switch to a full-screen text console (a virtual terminal). This step is crucial because without a terminal, you cannot interact with the command line at all.
Identify Your Shell and Prompt
Once the terminal opens, you'll see a prompt (e.g., 'user@hostname ~]$'). The default shell is bash. The prompt tells you whether you are a regular user (ending with $) or the root user (ending with #). Knowing your user level is important because many system commands require root privileges and will fail otherwise.
Run a Basic Command to Test the System
Type a simple command like 'pwd' (print working directory) and press Enter. The system will output the full path to your current directory (e.g., '/home/student'). This proves the shell is working and verifies your location in the file system. Always start with a simple test command to confirm the terminal is responsive before moving on to complex tasks.
Access the Manual Page for a Command You Don't Know
When you encounter a command you don't recognise, type 'man <command>' (e.g., 'man ls'). The man page opens in a pager (usually 'less'). Use the arrow keys to scroll, press 'q' to quit, and type '/keyword' to search for specific terms (e.g., '/human-readable'). This step is the core skill for finding documentation – never guess the syntax; always check the man page.
Search for Commands by Topic Using apropos
If you don't even know the command name, type 'apropos <topic>' (e.g., 'apropos network'). The system returns a list of all commands whose man page descriptions contain your keyword. Each result shows the command name, its man page section number, and a short description. This is how you discover the right tool for a task you've never done before.
Use the --help Option for Quick Syntax Reference
For a brief summary of a command's options without the full manual, type '<command> --help' (e.g., 'cp --help'). This prints a condensed help message directly to the terminal and then exits. It's faster than opening a man page when you just need to confirm one option's name or order. Use this for external commands when you're in a hurry.
Access Documentation for Shell Built-in Commands
For commands that come with the shell itself (like 'cd', 'echo', 'exit'), type 'help <command>' (e.g., 'help cd'). This shows the syntax and available options for that built-in command. Do not use 'man' for built-in commands – it will fail or show the documentation for a different tool with the same name.
You're a junior sysadmin at a mid-sized company that runs its internal web server on RHEL. The senior admin is on holiday, and the web server stops responding. You need to restart the Apache web server service, but you've never done it before. You're logged in via SSH (Secure Shell – a way to access a remote server securely over a network) from your laptop. There's no graphical interface, just a terminal prompt.
Here's exactly what you do: First, you need to find the exact name of the web server service. You remember it might be called 'httpd' or 'apache'. You type 'apropos web server' and see a list of commands related to web serving. Among the results is 'httpd(8)' – that's the daemon (background process) for Apache. You then type 'man httpd' to read the manual page. You scroll down to the SYNOPSIS section and see that to start the service, you typically use the 'systemctl start httpd' command, but you're not sure if you need to stop it first. You scroll further and see the 'SEE ALSO' section which points you to 'systemctl(1)'. You type 'man systemctl' and learn that 'systemctl restart httpd' will stop and start the service in one step.
Now you need to check if the service actually restarted successfully. You type 'systemctl status httpd' and see a green 'active (running)' status. But the website still isn't loading. You suspect a firewall issue. You type 'man firewall-cmd' to learn how to check which ports are open. The man page shows you that 'firewall-cmd --list-all' displays the current firewall configuration. You run it and see that port 80 (HTTP) is not listed. You then run 'firewall-cmd --add-service=http --permanent' to open the HTTP port permanently, then 'firewall-cmd --reload' to apply the change. The website starts working.
In a real business context, you wouldn't have the luxury of Googling – many production servers are isolated from the internet for security. The help tools on the command line become your lifeline. Sysadmins also use these tools daily to:
Write automation scripts that must run without human interaction, so every command's exact syntax must be verified in the man pages.
Audit system configurations by reading the documentation of packages they've never used before.
Train new team members by walking them through the command line help system – 'the answer is in the man page' is a common mantra.
Without knowing how to access the command line and get help, you'd be stuck waiting for the senior admin to return, costing the company revenue every minute the website is down. That's why the EX200 exam makes this your first objective.
The EX200 (now known as EX200 – Red Hat Certified System Administrator) exam places exceptional weight on Objective 1.1. It is the absolute foundation – you cannot pass the exam if you cannot navigate the command line and find documentation. The exam is entirely performance-based, not multiple choice. You are given a list of tasks and a live RHEL system to complete them on. The proctors watch your screen, and partial credit is rarely given.
What exactly does the exam test? You must demonstrate that you can:
Log into a system both locally (at the physical console) and remotely via SSH. They will test your ability to use 'ssh username@hostname' and to troubleshoot common connection issues (like wrong port or key permissions).
Switch between virtual consoles using Ctrl+Alt+F1 through F6. RHEL has multiple text-based terminals that you can access even if the graphical interface crashes. The exam expects you to know this escape route.
Use 'man' with section numbers. For example, 'man 5 passwd' opens the file format section for the password file, while 'man 1 passwd' opens the command section. You need to know that man pages are organised into sections: 1 (user commands), 5 (file formats and conventions), 8 (system administration commands).
Search within a man page using '/' followed by a keyword, and navigate with 'n' (next match) and 'N' (previous match). This is critical during the exam – you will not have time to read entire man pages.
Use 'apropos' and 'whatis' to find commands by topic. The exam loves a scenario like: 'You need to modify the system's date and time. Find the appropriate command using the man pages.' You must use 'apropos time' to find 'timedatectl' or 'date'.
Use the '--help' option (e.g., 'command --help') for a quick syntax summary. Many commands also support '-h', but '-h' is not universal (sometimes it means 'human-readable'). The exam expects you to know the difference and use '--help' when in doubt.
Understand the difference between built-in commands (like 'cd', 'echo', 'exit') and external commands (like 'ls', 'cp', 'man'). For built-in commands, 'help cd' works; for external commands, 'man ls' works. A common trap is typing 'help ls' – it will fail because 'ls' is not a shell built-in.
Common traps the exam sets:
They will ask you to find documentation for a command that does not exist. You must use 'apropos' to confirm no man pages match before concluding the command is not installed or does not exist.
They will give you a task that requires the 'info' page instead of the 'man' page. For example, GNU coreutils commands like 'cp' often have richer documentation in 'info' than in 'man'. If you only check 'man', you might miss key options.
They will disable your internet access (the exam machines are isolated). You cannot Google. You must rely solely on the system's built-in help.
They will test your ability to read and understand the 'SYNOPSIS' section of a man page, which uses special notation: square brackets [] mean optional, angle brackets <> mean required, and ellipsis ... means you can have multiple. You must interpret this correctly to construct the exact command.
Key definitions to memorise for the exam:
Shell: The command interpreter (bash is the default).
Terminal: The interface where you type commands.
man: Manual page system.
apropos: Search man page descriptions for a keyword.
whatis: Display a one-line description of a command.
info: GNU hypertext documentation browser.
/ (in man page): Initiate a forward search.
n / N (in man page): Jump to next/previous search result.
q (in man page): Quit the man page browser.
built-in: A command that is part of the shell itself (no separate executable file).
external command: A command that is a separate executable file stored in a directory (like /usr/bin).
The command line is a text interface where you type commands and the system responds with text output; the shell interprets what you type.
Every command follows the pattern: command_name [options] [arguments] – options modify behaviour and arguments specify what to act on.
Use 'man <command>' to view the manual page for most external commands; navigate by pressing 'q' to quit, 'h' for help, and '/' to search.
For shell built-in commands like 'cd' and 'exit', use 'help <command>' because they don't have separate man pages.
Use 'apropos <keyword>' to search through all man page descriptions when you don't know the exact command name.
The '--help' option provides a quick syntax summary for almost all commands, but avoid '-h' unless you are sure it means help, not something else.
Man pages are organised into numbered sections – section 1 for user commands, section 5 for file formats, and section 8 for system administration commands.
The EX200 exam is performance-based and requires you to discover command syntax using the system's built-in help tools, with no internet access.
SSH stands for Secure Shell and is the standard way to access a remote Linux server securely over a network.
You can switch between virtual consoles in RHEL by pressing Ctrl+Alt+F1 through F6 – a vital troubleshooting skill if the graphical interface freezes.
These come up on the exam all the time. Here's how to tell them apart.
man pages
Older format, standardised across Unix-like systems
Plain text, no hyperlinks between sections
Search with '/' – simple but limited navigation
info pages
Newer format from the GNU Project
Hypertext with links to related topics
Navigated with arrow keys and Tab – more complex but richer
External commands (e.g., ls, cp)
Separate executable files stored in directories like /usr/bin
Documentation via 'man' or '--help'
Can be used in scripts and pipelines independently of the shell
Shell built-ins (e.g., cd, exit)
Part of the shell program itself (no separate file)
Documentation via 'help' command only
Run faster because no separate process is spawned
whatis command
Shows one-line descriptions for exact command names
Output is short and specific
Use when you already know the command name
apropos command
Searches man page descriptions for any keyword
Returns multiple matches that may be related
Use when you don't know the command name at all
--help option
Produces a brief syntax summary directly in the terminal
Does not require a pager – prints and exits
Good for quick reminders of option names
man page
Provides full documentation with descriptions and examples
Opens in a pager (less) with search capabilities
Good for learning a command in depth
Mistake
The 'man' command shows documentation for every command, including ones that are built into the shell.
Correct
No, built-in commands (like 'cd', 'pwd', 'exit') do not have separate man pages because they are part of the shell itself. Use 'help <command>' instead.
Beginners assume all commands are external programs with their own manual pages. They don't realise the shell has its own set of internal commands.
Mistake
You can just type 'help' for any command and it will work.
Correct
'help' only works for shell built-in commands. For external commands (like 'ls', 'cp', 'man'), you must use 'man' or '--help'. Typing 'help ls' gives an error.
The word 'help' sounds universal, so beginners try it on everything. They don't understand the distinction between internal and external commands.
Mistake
The '--help' option and '-h' option always do the same thing.
Correct
'--help' is a long option that almost always shows a help summary. '-h' is a short option that can mean something completely different depending on the command (e.g., with 'ls -h', it means 'human-readable' file sizes).
Short options are concise but ambiguous across different commands. Beginners learn one meaning and assume it's consistent everywhere.
Mistake
The 'info' command is just a newer version of 'man' and is always better.
Correct
'info' is a separate system with hyperlinks, but not all commands have info pages. Many older or simpler commands only have man pages. Also, info pages can be harder to navigate if you're not used to the keybindings.
Beginners want a 'one best way' and don't realise that different help tools serve different purposes and may not be available for all commands.
Mistake
You can type 'man man' to learn about the 'man' command, but you can't use 'man' on itself.
Correct
Yes, you absolutely can type 'man man' – it opens the manual page for the man command, which explains how to navigate man pages, the sections, and the available options.
It sounds circular ('I need to use man to learn about man'), but beginners assume there's a special rule against it. There isn't.
Reveal each answer, then mark whether you got it right. Score 60%+ to unlock the next chapter.
Press Ctrl+Alt+F2 to switch to a text-based virtual console. You will see a login prompt where you enter your username and password. This works even if the graphical desktop is not running.
'man' displays traditional manual pages in a plain-text format. 'info' is a hypertext help system developed by the GNU Project that supports links between sections. Some commands (especially GNU tools) have more detailed documentation in 'info' than in 'man'.
Because 'ls' is an external command, not a shell built-in. The 'help' command only works for built-in commands like 'cd' and 'exit'. For 'ls', use 'man ls' or 'ls --help' instead.
Open the man page with 'man <command>', then press '/' to search within the page. Type a keyword related to what you want (e.g., 'recursive' for copying directories) and press Enter. Use 'n' to jump to the next match.
Use the 'apropos' command followed by a keyword. For example, 'apropos printer' will list all commands related to printing. Then look at the descriptions to find the one you need.
First, check if it's a shell built-in – if so, use 'help <command>'. If it's an external command with no man page, it may have an info page ('info <command>') or a --help option. As a last resort, check the /usr/share/doc/ directory for package-specific documentation files.
You've finished Accessing the Command Line and Getting Help. Continue through the EX200 study guide to build a complete picture of the exam.
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