Linux Commands
Command references for core Linux tools, syntax, examples, and practical one-liners.
ss Command in Linux: Display Socket Statistics
The ss command displays socket statistics and open ports and is the modern replacement for netstat. This guide explains how to list TCP, UDP, and Unix sockets, filter by port and state, and identify which process owns a socket.
pgrep Command in Linux: Find and Filter Running Processes
The pgrep command finds running processes by regex pattern, user, terminal, or parent PID and prints matching PIDs. This guide covers exact matching, filtering options, and script-friendly exit checks.
unlink Command in Linux: Remove a Single File
The unlink command removes a single file by deleting its directory entry. This guide explains how to use unlink, how it differs from rm, and what to expect when removing files and symbolic links.
uniq Command in Linux: Remove and Count Duplicate Lines
The uniq command removes or counts duplicate adjacent lines in a file. This guide explains how to filter duplicates, count occurrences, and use uniq with sort in pipelines.
Check Open Ports in Linux: nmap, netcat, and Bash
Three ways to check which ports are open on a Linux system from the command line: nmap, netcat, and the Bash /dev/tcp pseudo-device.
ifconfig Command in Linux: Configure Network Interfaces
Configure and view network interfaces in Linux using ifconfig. Covers IP assignment, enabling and disabling interfaces, MTU, MAC address changes, and modern ip command equivalents.
groupdel Command in Linux: Delete a Group
Learn how to delete a Linux group using the groupdel command. Covers syntax, verification, handling primary group errors, and what happens to files owned by the deleted group.
wc Command in Linux: Count Lines, Words, and Bytes
The wc command counts lines, words, characters, and bytes in files or standard input. This guide covers all options with practical pipeline examples.
top Command in Linux: Monitor Processes in Real Time
The top command displays running processes and system resource usage in real time. This guide covers sorting, filtering, load metrics, and key interactive controls.
usermod Command in Linux: Modify User Accounts and Groups
The usermod command modifies user account attributes such as groups, shell, home directory, username, and expiry date. This guide covers all common options with examples.
sort Command in Linux: Sort Lines of Text
The sort command sorts lines of text files alphabetically or numerically. This guide covers sorting by column, reverse order, unique lines, and combining sort with other commands.
wall Command in Linux: Broadcast Messages to Logged-In Users
The wall command broadcasts a message to the terminals of all logged-in users in Linux. This guide covers sending messages from arguments, files, and pipes, with group targeting and banner control.
journalctl Command in Linux: Query and Filter System Logs
journalctl queries the systemd journal and lets you filter logs by unit, time, priority, boot, and process. This guide covers the most useful journalctl options with practical examples.
stat Command in Linux: Display File and Filesystem Information
The stat command displays detailed file and filesystem information in Linux, including size, permissions, inode number, and timestamps. This guide covers all major stat options with examples.
How to Create Groups in Linux: groupadd Command
This guide explains how to create groups in Linux using the groupadd command, including how to set a custom GID, create system groups, and manage group options.
touch Command in Linux: Create Files and Update Timestamps
The touch command creates empty files and updates file timestamps in Linux. This guide covers access time, modification time, custom timestamps, and reference file usage.
Rsync Command in Linux with Examples
Learn how to use the rsync command to sync files and directories locally and remotely. Covers common options, remote transfers, dry run, exclusions, and troubleshooting.
Linux patch Command: Apply Diff Files
The patch command applies diff files to original files in Linux. This guide covers basic usage, strip paths, dry run, backup, and reversing patches with examples.
Timeout Command in Linux
The timeout command runs a specified command and terminates it after a given time limit. This guide covers syntax, signal handling, exit codes, and practical examples for scripts and pipelines.
Rmmod Command in Linux
Learn how to use the rmmod command to remove kernel modules in Linux, including options, troubleshooting, and best practices.
