Linux Commands
Command references for core Linux tools, syntax, examples, and practical one-liners.
umask Command in Linux: Set Default File Permissions
The umask command sets the default permission mask for newly created files and directories. This guide explains how umask works, how to calculate its value, and how to make it permanent.
head Command in Linux: Display the First Lines of a File
The head command prints the first lines or bytes of one or more files. Learn how to use head to preview files, limit pipeline output, and inspect logs.
ssh Command in Linux: Connect to Remote Servers
Connect to remote servers securely using the ssh command. Covers basic connections, key-based authentication, SSH config files, running remote commands, port forwarding, and troubleshooting.
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.
which Command in Linux: Find Executable Locations
The which command locates executables by searching the directories in your PATH. This guide covers syntax, options, and how which compares to type, whereis, and command -v.
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.
Linux basename Command: Strip Directory and Suffix from File Names
The basename command strips the directory path and optional suffix from a file name. This guide covers all basename options with practical examples.
Linux uname Command: Print System Information
The uname command prints kernel name, version, architecture, and hostname. This guide covers all uname options with examples and practical scripting uses.
