$ command library

Creates a group.

Creates a user (interactive, Debian/Ubuntu).

Creates or displays shell aliases.

Searches manual page descriptions for keywords.

Manages packages on Debian/Ubuntu.

Queries the APT package cache.

Installs, upgrades, or removes packages from the internet (Debian/Ubuntu).

Displays and modifies the ARP cache.

Shows and modifies the ARP cache, which maps IP addresses to MAC addresses of hosts on your local network.

Displays or modifies file extension associations.

Schedules a command to run once in the future.

Displays or changes file and directory attributes. Attributes: a (archive), r (read-only), h (hidden), s (system).

Processes text by fields and rules.

Encodes data as Base64 or decodes it. It turns binary content into text that can be copied or sent by email.

Strips the directory from a path and leaves only the file name. It can also strip a suffix, such as the extension.

Resumes a suspended job in the background.

Shows the UUID, label and file system type of block devices, such as disks and partitions.

Compresses files into .bz2 format. Levels from -1 (fastest) to -9 (best compression).

Displays a calendar.

Calls a subroutine or another .bat script.

Displays file contents.

Changes the current directory.

Changes the current directory.

Shows and changes an account's password aging policy: maximum days, warnings and expiry date.

Changes group ownership.

Checks a disk for errors.

Checks or schedules chkdsk at boot time for NTFS drives.

Changes file or directory access permissions.

Shows a question with several single-key options and stores the chosen one in ERRORLEVEL, for use in .bat scripts.

Change file owner and group.

Changes an account's login shell. It only accepts shells listed in /etc/shells.

File/folder encryption on NTFS (EFS).

Clear the terminal screen.

Copies the output of a command to the clipboard.

Clears the screen.

Starts a new instance of the command interpreter.

Compare two files byte by byte.

Changes the console window colors. 1st digit = background, 2nd = foreground (hex 0-F).

Formats its input into columns. With -t it aligns the fields like a table, which makes long output easier to read.

Binary file comparison.

File and folder compression at the NTFS file system level.

Converts a FAT/FAT32 volume to NTFS without deleting files.

Copies files to another folder. Wildcards: * and ?.

Copy files and directories. Wildcards: * (any number of characters), ? (0 or 1 character).

Maintain crontab files for periodic background jobs.

Transfer data from or to a server using multiple protocols.

Transfers data to or from a server by URL (HTTP, HTTPS, FTP...). It ships with Windows 10 and 11 as curl.exe.

Remove sections from each line of files (fields or characters).

Display or set the system date and time.

Displays or sets the system date.

Copies and converts data block by block between files and devices. It is used to clone disks, create images or generate test files.

Analyzes fragmentation and defragments a drive.

Deletes files.

Remove a group.

Remove a user.

File system disk space usage information.

Compare two files as text and display differences.

DNS lookup utility.

Displays the contents of a directory.

Returns only the directory part of a path, removing the last component.

Interactive tool to manage disks, partitions, and volumes.

Manages Windows images and components.

Shows the kernel message buffer: boot, hardware detection, drivers and system errors.

DNS domain name.

Manages the console command history and creates macros: shortcuts that expand into full commands.

Manage local .deb packages.

Manipulate .deb archives (inspect, extract).

Query the dpkg package database.

Reconfigure an already installed package.

Lists installed drivers.

Estimate file or directory space usage.

Display a line of text.

Displays messages or turns command echoing on or off in a script.

Terminal-based text editor (classic Windows/DOS versions).

Searches for lines matching an extended regular expression. It is equivalent to grep -E.

Eject CD-ROM tray or removable media.

Display or modify the environment before executing a command.

Deletes files (alias of del).

Close the terminal window or session. Accepts an optional exit status.

Quits the command interpreter window.

Set an environment variable and export it to child processes.

Does nothing and always exits with status 1, which means failure. It is used to test scripts and conditions.

Compares files in text or binary mode.

Manipulates disk partition tables (MBR/GPT).

Moves a background job to the foreground.

Determines file type by inspecting its contents.

Searches for files in a directory hierarchy based on various criteria. Supports logical operators with -a (and), -o (or), and ! (not).

Searches for a string in a file or command output.

Searches for patterns and regular expressions in files.

Displays user information lookup program.

Repeats a command for each element of a set: files, folders, numbers or lines of a file.

Formats a drive (changes the file system).

Displays amount of free and used memory in the system.

Checks and repairs a Linux file system.

Advanced NTFS file system utilities: free space, volume information, creating test files and system behaviour.

Displays or modifies file types and associated open commands.

Queries the system databases (users, groups, hosts, services) honouring the configured sources, not just local files.

Shows the access control lists (ACLs) of files and directories: extra permissions for specific users and groups.

Shows the MAC addresses of the machine's network adapters, or of a remote computer.

Version control system: it keeps a project's change history and lets you go back, branch and collaborate.

Jumps to a label in a .bat script and continues execution from there. It allows loops, menus and early exits.

Creates and manages disk partitions (graphical interface).

Manages groups: adds or removes members, sets the full member list or names group administrators.

Shows which group policies are being applied to the computer and the user, and where they come from.

Refreshes the computer and user group policies without waiting for the next automatic cycle.

Search for a pattern in one or more files.

Creates a new group on the system. You can set the GID by hand or let the next free one be assigned.

Deletes a group from the system. By default it refuses to delete a group that is some user's primary group.

Modify a group definition on the system.

Display the groups to which a user belongs.

Compress a file to .gz (replaces the original unless -k is specified).

Output the first part of files.

Display information about bash builtin commands.

Displays command help.

Display or manipulate the history list.

Makes simple DNS queries: it resolves a name to its IP address, or an IP to its name, and queries other record types.

Display or set the system's host name.

Displays the computer name.

Shows and changes the host name and other system data, such as the operating system and kernel, through systemd.

Display or set the hardware clock (RTC).

Shows and modifies the NTFS permissions (access control lists) of files and folders.

Print user and group information (UID, GID, groups).

Runs a command only if a condition is met: if a file exists, if two texts are equal, if the error code is greater than a value...

Shows and configures network interfaces with the classic syntax. It is obsolete compared with ip, but still appears in many manuals.

Read documentation in hypertext format.

Show and configure network interfaces, addresses, and routing.

Displays and manages IP configuration.

Configures the kernel's packet filtering rules: what traffic comes in, goes out or is forwarded. It is the base of many Linux firewalls.

List background jobs running in the current shell.

Query and view system logs managed by systemd.

Send a signal to a process by PID.

Kill processes by name.

Changes the label of a drive or volume.

Show a listing of last logged in users.

Shows the most recent login of every account on the system, with the port and origin.

Advanced pager (allows forward and backward navigation).

Create links between files (hard link by default, symbolic with -s).

Get locale-specific information (language, character encoding).

Find files by name using an indexed database, much faster than find.

Logs off a user session, the current one or one with a given ID, on the local computer or a remote one.

Exit the current user session.

Submit a file for printing.

List directory contents.

Shows information about the installed Linux distribution: name, version and codename.

List block devices in a tree-like format.

Shows CPU information: architecture, model, number of cores and threads, frequencies and caches.

List hardware configuration.

Shows the kernel modules that are loaded, with their size and which other modules use them.

Lists open files and which process uses them. On Linux almost everything is a file, so it also shows network connections and listening ports.

Lists the devices connected to the PCI bus: graphics card, network, disk controllers, and so on.

Lists the connected USB devices and the buses they belong to.

An interface to the system reference manuals.

Creates a directory or folder.

Computes and verifies MD5 checksums, which are used to detect whether a file got corrupted or changed.

Create directories.

Creates a directory or folder (alias for md).

Build a Linux filesystem on a device.

Creates symbolic links, hard links and junctions between files and folders.

Configures system devices: the size and properties of the console, keyboard speed and serial ports.

Display text one screen at a time.

Displays paginated output.

Mount a filesystem or storage device.

Moves a file to another folder.

Move (rename) files and directories.

Simple terminal text editor.

Shows NetBIOS over TCP/IP statistics and connections: names, name cache and sessions.

Netcat: opens TCP and UDP connections from the command line. It is used to test ports, send data and set up simple servers.

Manages users, groups, shared resources, network connections, and services.

Windows network configuration tool: it shows and changes interfaces, the firewall, Wi-Fi and the network stack from the command line.

Displays network connections, listening ports, and routing tables.

Displays network connections, ports, and statistics.

Changes the current session's primary group to another group you already belong to, opening a new shell.

Runs a process with an adjusted scheduling priority (-20 high, 19 low).

Numbers lines of a file.

Network and port scanner: it discovers live hosts, open ports and the services they offer.

Runs a command that ignores the hangup signal, so it keeps running after you leave the terminal.

Prints the number of processing units (CPUs) available to the current process.

Queries DNS servers and records.

Queries DNS.

Creates and manages partition tables and partitions (text mode).

Changes a user's password.

Merges files line by line, placing each line of one file next to the line in the same position of the others.

Displays or sets the PATH variable.

Combines traceroute and ping to analyze packet loss and latency.

Pauses execution until a key is pressed.

Searches for processes by name and returns their PIDs.

Returns the process IDs (PIDs) of the processes running a given program.

Check network connectivity by sending ICMP packets.

Tests connectivity using ICMP.

Python package installer: it installs, upgrades and uninstalls libraries from the PyPI repository.

Send a signal to processes matching a pattern.

Returns to the directory saved by the last pushd and removes it from the stack; if it was a temporary network drive, it releases it.

Power off the system.

Prints a text file to a printer.

Print all or part of the environment.

Format and print text.

Changes the Command Prompt appearance.

Report a snapshot of the current processes.

Display running processes as a tree.

Saves the current directory on a stack and changes to another one, so you can return later with popd. With a network path it creates a temporary drive.

Print the current working directory.

Shows the user sessions open on a computer: who is connected, from where and since when.

Removes an empty directory.

Reads a line from standard input and stores it in one or more variables. It is used to ask the user for data in scripts.

Converts a path into its canonical absolute form: it resolves ., .. and symbolic links.

Reboots the system.

Queries and modifies the Windows Registry from the command line: it adds, deletes, exports and imports keys and values.

Marks the rest of the line as a comment in a .bat script, which is neither run nor shown.

Renames a file or folder.

Renames a file or folder (alias of ren).

Alters priority of running processes.

Replaces existing files or adds new files to a destination directory.

Resets the terminal to its default state (useful when displaying garbled output).

Reverse lines characterwise.

Remove files or directories (including non-empty ones with -R).

Remove empty directories.

Removes an empty directory (alias of rd).

Robust file and directory copy; includes retry and mirroring capabilities.

Displays and modifies the IP routing table.

Shows and modifies the system routing table with the classic syntax. Its modern replacement is ip route.

Synchronizes files and directories locally or remotely, copying only differences.

Runs a program with another user's credentials, for example an administrator, without logging out.

Manages Windows services.

Creates, queries, runs and deletes scheduled tasks from the command line.

Copies files over SSH.

Processes and transforms text using expressions.

Generates a sequence of numbers, with configurable start, step and end. It is very useful in loops and scripts.

Starts, stops and queries services using the classic syntax. On systems with systemd it forwards the commands to systemctl.

Displays or sets environment variables in CMD.

Sets or modifies the access control lists (ACLs) of files and directories, to grant permissions to specific users or groups.

Creates or modifies environment variables permanently, for the user or the whole system.

Scans and repairs errors in system files.

Computes and verifies SHA-256 checksums. It is the usual way to verify downloads such as ISO images.

Powers off or reboots the system (can be scheduled).

Shuts down, restarts, or signs out.

Pauses for N seconds.

Sorts lines of text files.

Sorts lines of a file or input.

Runs a script inside the current shell, so the variables, aliases and functions it defines stay available in your session.

Dumps socket statistics and network connections.

Connects to a remote system using SSH.

Generates and manages SSH keys to authenticate without a password. It creates a pair: a private key, which you keep, and a public key, which you copy to the server.

Starts a program or opens a new window.

Displays detailed file status: size, permissions, inode, and timestamps.

Switches to another user (substitute user).

Creates virtual drives associated with a path.

Execute a command as administrator (root).

Control system services and units managed by systemd.

Detailed hardware and OS information.

Output the last part of files.

Takes ownership of a file or folder, so you can then change its permissions when the current owner does not let you in.

Archive files and directories. When combined with -z (gzip) or -j (bzip2), it also compresses.

Creates and extracts archives (.tar, .tar.gz, .zip). It ships with Windows 10 and 11, based on bsdtar.

Terminates a process by PID or name.

Displays currently running processes.

Read from standard input and write to standard output and files.

Telnet client: it opens an unencrypted text connection to a host and port. Today it is mostly used to check whether a port answers.

Evaluates a condition about files, strings or numbers and returns an exit status: 0 if true and 1 if false. [ ... ] is its equivalent form.

Displays or sets the system time.

Shows and changes the system date, time and time zone, and controls synchronization with NTP servers.

Runs a command and terminates it if it takes longer than the given time. It is useful to stop a process from hanging.

Waits the given number of seconds, or until a key is pressed. It is the usual way to pause a .bat script.

Sets the window title.

Display Linux processes.

Change file timestamps or create an empty file.

Translate or delete characters.

Shows the path of hops (routers) that packets follow to a destination, with each one's response time.

Displays the path to a destination using hops.

Displays directory contents in a tree-like format.

Displays a directory tree.

Does nothing and always exits with status 0, which means success. It is used in infinite loops and to force a success.

Indicates how the shell interprets a command name.

Displays the contents of a text file.

Simple firewall (Uncomplicated Firewall): it allows or blocks traffic with easy-to-read rules, on top of iptables.

Shows and sets the resource limits of the current shell and the processes it launches, such as open files or processes.

Displays or sets the default permission mask.

Unmounts a filesystem.

Removes shell aliases.

Displays system information.

Removes consecutive duplicate lines (commonly used with sort).

Removes variables or functions from the current shell, so they stop existing in the session.

Extracts and lists files in ZIP archives.

System uptime.

Create a new user account on the system.

Deletes a user account from the system. With -r it also removes the home directory and the mail spool.

Modify an existing user account.

Currently logged in users (simple list).

Displays the Windows version.

Enables or disables disk write verification.

Modal terminal text editor, widely used in system administration.

Edits /etc/sudoers by locking it and checking the syntax before saving, so sudo is not left unusable.

Shows system statistics: processes, memory, swap, input/output, interrupts and CPU usage.

Displays the volume label and serial number.

Show who is logged on and what they are doing.

Wait for a process or job to complete.

Runs a command repeatedly every few seconds and shows its output full screen, so you can watch it change.

Count lines, words, and characters.

Queries, exports and manages Windows event logs from the command line.

Download files using HTTP, HTTPS, or FTP.

Display one-line manual page descriptions.

Locates files matching a pattern in PATH or a specified directory.

Locate an executable in the PATH.

Show who is logged on.

Print the current username.

Displays currently logged-on user information.

Queries the registration data of a domain or an IP address: holder, dates, name servers and registrar.

Windows Management Instrumentation (WMI) command-line utility.

Build and execute command lines from standard input.

Copies files and directory trees.

Output a string repeatedly until killed (defaults to 'y'). Useful for auto-confirming prompts.

Package manager for older RHEL, CentOS, and Fedora releases.

Creates ZIP archives.