Linux VPS · Beginner Reference
Permissions & Users
Everything you need to understand Linux users, directories & permissions
01 · Prompt
Reading the Shell Prompt
root
@
srv1628184
:
~
#
- root Current logged-in username — the superuser/administrator
- @ Separator meaning “at”
- srv1628184 Hostname of your server
- ~ Current directory — tilde = home folder (
/rootfor root user) - # You are root. Regular users see
$instead
02 · Directories
Key Directory Structure
/ ← root of the entire filesystem
├── root/ ← root user’s home folder
├── home/ ← regular users live here
│ ├── john/ ← john’s private folder
│ └── mary/ ← mary’s private folder
├── etc/ ← system config files
└── var/ ← logs, web files, etc.
- /root Root’s private home — nobody else can enter
- /home/user Each user owns their own folder only
- ~ Shortcut for your own home — changes per user
03 · Permission String
How to Read Permissions
–
r
w
x
|
r
–
x
|
r
–
–
type
r
w
x
r
–
x
r
–
–
| Who | Permissions | Meaning |
|---|---|---|
| Owner | r w x | Read, Write & Execute |
| Group | r – x | Read & Execute only |
| Others | r – – | Read only |
04 · Access Types
What r · w · x Mean
| Symbol | Name | On a File | On a Folder |
|---|---|---|---|
| r | Read | Open & view it | List files inside |
| w | Write | Edit or delete | Create/delete files inside |
| x | Execute | Run as a program | Enter with cd |
| – | Denied | Permission not granted | |
💡 A folder needs
x to enter it with cd. Without it you get Permission denied even if you can see the folder.
05 · Access Matrix
Who Can Access What
| Directory | root | owner | other user |
|---|---|---|---|
| / | ✓ | read only | read only |
| /root | ✓ | ✗ | ✗ |
| /home/john | ✓ | ✓ | ✗ |
| /home/mary | ✓ | ✓ | ✗ |
| /etc | ✓ | read only | read only |
⚠️ root overrides everything. Root can read, write and execute any file on the system regardless of what permissions are set.
06 · Commands
Essential Commands
$
ls -la
list files with permissions
$
pwd
show current directory path
$
whoami
show current username
#
adduser john
create a new user
#
usermod -aG sudo john
give sudo privileges
#
chmod 755 folder/
set folder permissions
#
chown john file.txt
change file owner
✅ # prompt = root · $ prompt = regular user.
Use
Use
sudo command as a regular user to run something as root.