The most dangerous command a new admin learns

[TudorRaduta]

The Temptation of `chmod 777`

Happy Wednesday, everyone!

It's time for our weekly "Problem & a Polish," where we talk about a common mistake that teaches us an important lesson. Today's topic: the most tempting and dangerous command a new sysadmin learns.

The Problem: You’re setting up an application, and it keeps failing with a "Permission denied" error. You're frustrated and you just want it to work. So you run the magic command: chmod -R 777 /path/to/app. It works! But you've just created a massive security hole.

Instead of opening the floodgates, the real sysadmin skill is to diagnose the specific permission needed. This is the principle of "least privilege."

The Polish: The Right Way to Troubleshoot

1. Check Ownership: First, see who owns the file with ls -l. Maybe the real fix is a quick chown.
2. Check Group: Is the user in the correct group? Check with groups username. Maybe the fix is chgrp.
3. Apply Correct Permissions: Grant only the exact permissions needed. For a config file, that might be chmod 640.

Your Turn!

1. What was the first "permission denied" puzzle that really forced you to learn chmod, chown, and chgrp properly?
2. What's your go-to command for quickly checking permissions and ownership?

Share your stories and tips in the comments!

[Chetan_Tiwary_]

Apart from ls , if you want more detailed information about the file - like access mode, selinux context : stat is another goto utility :

or else you have namei utility :

[Blue_bird]

Thanks for stat and namei commands @Chetan_Tiwary_ 

[DamianB]

Especially when creating new users on servers or VMs, configuring SSH, generating new keys, or copying existing keys from the host to clients.
A huge time-saver!