Linux Tutorial for Beginners: The Commands You'll Actually Use

01.Navigating the file system

Linux is a tree starting at `/`. Everything is a file — including devices, sockets and process info. Get comfortable with `pwd`, `cd`, `ls -la`, `tree` and `find` before you do anything else.

$ pwd
/home/arjun
$ ls -la
drwxr-xr-x 5 arjun arjun 4096 Jun 13 09:12 .
drwxr-xr-x 3 root  root  4096 Jan  4 11:01 ..
-rw------- 1 arjun arjun  220 Jan  4 11:01 .bash_history

02.Permissions: read, write, execute

Every file has an owner, a group and three permission triplets. `chmod 644` (rw-r--r--) for files and `755` (rwxr-xr-x) for directories cover most cases. `chown user:group file` changes ownership.

03.Processes and signals

Use `ps aux | grep nginx` to find a process. Use `htop` to see them live. `kill -9 <pid>` is the nuclear option — try `kill <pid>` (SIGTERM) first to let the process clean up.

04.Networking quick wins

`ss -tulpn` lists listening ports. `curl -I example.com` checks HTTP. `dig example.com` checks DNS. `ip a` shows interfaces. These four commands debug 80% of 'is the server even reachable' questions.

05.A useful shell script in 15 lines

Automate the boring stuff. Below is a script that compresses log files older than 7 days — the kind of task every Linux admin gets asked to do in their first week.

#!/usr/bin/env bash
set -euo pipefail
LOG_DIR=/var/log/myapp
find "$LOG_DIR" -name "*.log" -mtime +7 -print0 | while IFS= read -r -d "" f; do
  echo "Compressing $f"
  gzip "$f"
done