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LaTerral Williams
LaTerral Williams

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🧠Need Info on a Linux Command? Linux Has You Covered!... Well, Kind of

#cloudwhistler #linux #redhat #cloud

Whether you're deep in the terminal or just starting to explore Linux, one thing is certain:

You’ll eventually run into a command, where you need more information.

Good news... Linux has ways to help you out.

Even better news... If "help" is missing you can install an assist! 🏀🤝🎯

In this post, we’ll explore helpful tools to search for command info in Linux (primarily RHEL9):

  • man (manual pages)
  • info (GNU documentation)
  • tldr (too long; didn’t read – community-based help)
  • wikit (quick lookups via wikipedia)

Let’s go!

📑 Table of Contents

🧾 man: The Manual We All Forget Exists

What it is:

The man command is your first stop for command help. It shows the manual pages for a command.

How to use: 

man ls
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You’ll get the manual page for ls, explaining options like -l, -a, and so on.

👉 Tip: Use / to search inside the man page. For example:

/recursive
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Need to install it?

On most Linux distros, man is usually installed by default. But if it's missing:

sudo dnf install man-db
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📚 info: For the Detail-Oriented Nerd in All of Us

What it is:

info provides more detailed (and sometimes more confusing) documentation.

How to use: 

info ls
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This gives you a more structured, navigable interface than man.

🔍 Use n for next page, p for previous, and q to quit.

Install it (if missing): 

sudo dnf install info
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Pro tip: If info is too much, just use man.

⚡ tldr: Man Pages for People in a Hurry

What it is:

tldr stands for “Too Long; Didn’t Read.” It gives you short, to-the-point command examples.

How to use: 

tldr useradd
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Much nicer than squinting through paragraphs of text, right?

Image description

Install it:

tldr likely isn't installed by default, but here's some steps to install it:

First, install Node.js:

sudo dnf module enable nodejs:18 sudo dnf install nodejs
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Then install tldr:

sudo npm install -g tldr
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And finally, update the cache:

tldr --update
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If you have trouble with tldr, here's some troubleshooting steps that helped me: 🧼 Troubleshooting Guide

🌐 wikit: Wikipedia Summaries in the Terminal

What it is:

A command-line tool that fetches pages from Wikipedia. It's not officially part of Linux but can be super helpful for information outside of terminal commands.

How to use: 

wikit AWS ECS
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Image description

Install wikit:

You’ll need Node.js first, since wikit is a Node-based CLI tool.

Enable and install Node.js 18: 

sudo dnf module enable nodejs:18 -y sudo dnf install nodejs -y
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Install wikit globally with npm: 

sudo npm install -g wikit
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🔍 Bonus Tip: Searching for Commands by Description

Sometimes you don’t know the command, just what you want to do... That’s where apropos shines:

apropos archive
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It’ll show commands related to “archive,” like tar, zip, etc.

You can also do:

man -k archive
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It does the same thing!

📊 Tool Comparison Table

Here’s a handy comparison of all four tools:

Tool Description Best For Install Command
man Traditional manual pages Full documentation sudo dnf install man-db
info GNU-focused hierarchical docs Detailed navigation sudo dnf install info
tldr Simplified examples Fast reference sudo npm install -g tldr
wikit Pulls from web wikis Community insights sudo npm install -g wikit

🧼 Cleanup

If you installed tools just for testing, feel free to remove them later:

sudo dnf remove nodejs man-db info sudo npm uninstall -g tldr sudo npm uninstall -g wikit
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🧰 Troubleshooting Guide (tldr)

I ran into some trouble with the tldr setup. Here's some steps I followed to resolve this issue and complete the install.

🔒 1. Fix curl: (91) SSL certificate/OCSP errors

If you see errors like:

curl: (91) SSL server certificate status verification failed: OCSP response has expired
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You likely need to reinstall your system's CA certificates and fix the clock.

✅ Step 1: Ensure CA certificates are present 

sudo dnf install ca-certificates sudo update-ca-trust force-enable sudo update-ca-trust extract
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🕒 2. Fix system clock issues (important for SSL & OCSP)

Out-of-sync clocks can break HTTPS and package verification. Fix it:

sudo dnf install chrony -y sudo systemctl enable --now chronyd sudo chronyc makestep
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This syncs your system time using public NTP servers.

📦 3. Check and enable AppStream (needed for modules like Node.js)

RHEL module streams like nodejs:18 depend on the AppStream repo being available.

✅ Step 1: Confirm AppStream is enabled 

sudo dnf repolist
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Look for a line like:

appstream Red Hat Enterprise Linux 9 AppStream
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If it’s missing, enable it:

sudo dnf config-manager --set-enabled appstream
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Then refresh the cache:

sudo dnf clean all sudo dnf makecache
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✅ Step 2: Enable your desired module (e.g., Node.js 18) 

sudo dnf module list nodejs sudo dnf module enable nodejs:18
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If this still fails, consider using an alternative like nvm (Node Version Manager), which installs Node.js without relying on system modules.

🧼 Bonus: Bypass OCSP checks in curl (if needed)

If nothing else works and you're stuck with expired OCSP responses, you can bypass revocation checks in curl (not recommended long-term):

curl --ssl-no-revoke https://example.com
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🎯 Final Thoughts

Linux gives you a toolbox, you just have to know where to look. Between man, info, tldr, and wikit, you can go from clueless to command-line wizard without leaving your terminal.

Pick the one that matches your vibe:

  • man for the classics 🧓
  • info if you like documentation trees 🌲
  • tldr for fast learners ⚡
  • wikit for crowdsourced wisdom 🌐

Which one’s your favorite? Drop a comment below or share your go-to terminal help trick!

💬 Let’s Connect

https://www.linkedin.com/in/ltwilliams-tech/

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