10 Essential Linux Commands to Turn a Beginner into a Pro

Open vs. closed source OS

Open‑source operating systems can be examined by many people, so bugs are discovered and fixed more quickly, resulting in more stable, secure, and efficient releases. Closed‑source systems may have slower bug discovery and lower‑quality fixes.

Basic user management commands

adduser user_name    # add a new user named user_name

passwd user_name    # set login password for user_name

userdel user_name    # delete the user named user_name

ls command

Purpose: list directory contents or file information.

ls -l    # detailed file information

ls -a    # include hidden files (those starting with .)

ls -d    # display directory entries themselves, not their contents

ls -i    # show inode number

ls -k    # display size in kilobytes

ls -n    # show numeric UID/GID instead of names

ls -F    # append a character to indicate file type (* executable, / directory, @ symlink, | FIFO, = socket)

ls -r    # reverse sort order

ls -t    # sort by modification time

ls -s    # show size after the filename

ls -R    # recursively list sub‑directories

ls -1    # one entry per line

File concept

A file consists of content plus attributes (metadata). Operations therefore target either the data or the metadata.

pwd command

Displays the current working directory.

cd command

Change directory: cd directory_name. Special shortcuts: ~ returns to the home directory, - returns to the previous directory.

File attribute basics

Attributes indicate type: a leading - denotes a regular file, d denotes a directory. Permissions are split into three groups—owner, group, and others—each with read ( r), write ( w), and execute ( x) bits.

mkdir command

Create a directory: mkdir directory_name.

rm command

Delete files or directories.

rm -f    # force deletion

rm -r    # recursively delete directories

touch command

Update a file’s access and modification timestamps, or create an empty file if it does not exist.

touch file_name

stat command

Display detailed file attributes (size, timestamps, permissions, etc.).

tree command

Show a visual directory tree.

tree path

man command

Show the manual page for a command.

man command_name

which command

Locate the executable file associated with a command.

which command_name

alias command

Create an alias (shortcut) for another command.

I/O redirection

Input redirection: < file feeds a file’s contents to a command.

Output redirection: > file writes command output to a file, overwriting existing content.

Append redirection: >> file appends command output to the end of a file.

Linux “everything is a file” principle

In Linux, virtually all resources—devices, sockets, pipes—are represented as files, allowing uniform handling of I/O.