Linux Commands

Command references for core Linux tools, syntax, examples, and practical one-liners.

Padlock illustration labeled /etc/passwd

Jun 20, 2026 • 5 min read • series

/etc/passwd in Linux: File Format and Fields Explained

The cat /etc/passwd command displays local Linux accounts. This guide explains its seven fields and when to use getent passwd instead.

Scheduling one-time tasks with the at command in Linux

Jun 20, 2026 • 7 min read

at Command in Linux: Schedule One-Time Tasks

The at command schedules one-time tasks to run at a specific time in Linux. This guide covers syntax, time formats, batch jobs, listing and removing jobs, and user restrictions.

Bash subshells shown as an isolated child shell inside a parent shell

Jun 17, 2026 • 6 min read • new • series

Bash Subshells: Isolate Variables and Directory Changes

Bash subshells run commands in an isolated shell environment. This guide explains parentheses, variable scope, directory changes, command substitution, pipelines, and exit codes.

Jun 15, 2026 • 5 min read • new

hostnamectl Command in Linux: Set and Query Hostname

Use hostnamectl to view and change the Linux hostname. Covers static, transient, and pretty names, system metadata, remote hosts, and common errors.

hostnamectl changing a Linux system name from old-host to web-server-01

Jun 14, 2026 • 6 min read • new

host Command in Linux: DNS Lookup

The host command is a simple DNS lookup tool. This guide covers forward and reverse lookups, querying specific record types, using a chosen name server, and reading the output.

Running DNS lookups with the host command in a Linux terminal

Jun 13, 2026 • 4 min read

pidof Command in Linux: Find Process IDs by Name

The pidof command finds the process ID (PID) of a running program by name. This guide explains how to use pidof, its options, and how to pair it with kill to manage processes.

Jun 11, 2026 • 8 min read • series

Linux Pipes Explained: How to Use the | Operator

Linux pipes connect command output to another command's input. Learn the | operator, pipefail, stderr piping, xargs, named pipes, and process substitution.

Linux commands connected through a shell pipeline

Jun 10, 2026 • 4 min read

Linux Time Command

This guide shows how to use the Linux time command to measure execution time, explains real/user/sys, and covers Bash, Zsh, and GNU time.

Jun 10, 2026 • 4 min read

Uptime Command in Linux

The uptime command shows how long a Linux system has been running, the number of logged-in users, and the load averages for the last 1, 5, and 15 minutes.

Jun 8, 2026 • 7 min read

pnpm Command: Install and Manage Node.js Packages

This pnpm command guide covers installation, project setup, dependency management, scripts, lockfiles, npm migration, and workspace filtering.

Managing Node.js packages with pnpm commands in a terminal

Jun 7, 2026 • 8 min read

ls Command in Linux: List Files and Directories

The ls command lists files and directories in Linux. See how to use ls -l, ls -al, hidden-file options, sorting, and other practical combinations.

Jun 5, 2026 • 7 min read

npm Command: Install and Manage Node.js Packages

This npm command guide covers project setup, local and global package installs, npm ci, updates, dependency removal, scripts, and one-off package runs.

Managing Node.js packages with the npm command in a Linux terminal

Jun 4, 2026 • 5 min read

Fix "sudo: command not found" on Linux

How to fix the 'sudo: command not found' error on Linux by installing the sudo package, adding your user to the right group, and recovering from a broken PATH.

Fixing the sudo command not found error on Linux

Jun 2, 2026 • 4 min read

Grep Multiple Patterns: Match Strings, Words, and Regex

Search for multiple patterns or strings at once with grep using the -e flag, fixed-string matching, alternation, and pattern files.

Grep Multiple Strings, Words, and Patterns

Jun 2, 2026 • 5 min read

chgrp Command in Linux: Change File Group Ownership

The chgrp command changes the group ownership of files and directories in Linux. This guide covers syntax, recursive changes, symlink handling, and practical examples.

Using the chgrp command to change group ownership in Linux

Jun 1, 2026 • 5 min read

dpkg Command in Linux: Install and Manage Debian Packages

Use dpkg to install, remove, query, and inspect Debian packages on Ubuntu, Debian, and other Debian-based distributions.

dpkg package management cards for installing, querying, and removing deb packages

May 31, 2026 • 4 min read

reboot Command in Linux: Restart with systemctl and shutdown -r

Three commands cover common Linux reboot scenarios: reboot for an immediate restart, systemctl reboot for the systemd path, and shutdown -r for scheduled restarts with user notifications.

Rebooting a Linux system from the command line using systemctl and shutdown

May 31, 2026 • 6 min read

CPU Info on Linux: Check CPU Details from the Command Line

Two commands give you everything about your CPU on Linux: /proc/cpuinfo for raw per-core details, and lscpu for a readable summary. See how to use both.

Checking CPU information on Linux using lscpu and /proc/cpuinfo

May 30, 2026 • 7 min read

tr Command in Linux: Translate, Delete, and Squeeze Characters

The tr command translates, deletes, and squeezes characters from standard input. This guide covers tr syntax, character sets and ranges, case conversion, removing line endings, and practical pipeline examples.

Using the Linux tr command to translate and delete characters

May 30, 2026 • 8 min read

Understanding the /etc/fstab File in Linux

The /etc/fstab file defines how filesystems and storage devices are mounted at boot. This guide explains the fstab format, field meanings, mount options, and how to add new entries safely.

The /etc/fstab file shown as a Linux storage configuration map