What Is a Command Line Interpreter?

Command line interpreter definition & common command line interfaces

A command line interpreter is any program that allows the entering of commands and then executes those commands to the operating system. It’s literally an interpreter of commands.

Unlike a program that has a graphical user interface (GUI) like buttons and menus that are controlled my a mouse, a command line interpreter accepts lines of text from a keyboard as the commands and then converts those commands into functions that the operating system understands.

Other Names for a Command Line Interpreter

Any command line interpreter program is also often referred to in general as a command line interface. Less commonly, it’s also called a CLI, command language interpreter, console user interface, command processor, shell, command line shell, or a command interpreter.

CLI is also an acronym for other technology terms that have nothing to do with a command line interface, such as calling line identfiication, call level interface, cache-line interleaving, clear interrupt flag, and caller location information.

Why Are They Used?

If a computer can be controlled through easy-to-use applications that have a graphical interface, you might wonder why anyone would want to instead enter commands through command line. There are three main reasons.

The first is that you can automate the commands. There are many examples we could give but one is a script to always shut down certain services or programs when the user first logs in. Another can be used to copy files of a similar format out of a folder so you don’t have to sift through it yourself. These things can be done fast and automatically by using commands.

Another benefit to using a command line interpreter is that you can have direct access to the functions of the operating system. Advanced users may prefer the command line interface because of that concise and powerful access that it gives them.

However, simple and inexperienced users don’t usually want to use a command line interface because they’re definitely not as easy to use as a graphical program. The available commands are not as obvious as a program that has a menu and buttons. You can’t just open a command line interpreter and immediately know how to use it like you can with a regular graphical application you might download.

Command line interpreters are useful because while there may be a huge number of commands and options for controlling an operating system, it’s possible that the GUI software on that operating system simply isn’t built to utilize those commands. They also let you use some of those commands while not having to use all of them at once, which is beneficial on systems that don’t have the resources to run a graphical program.

Not All Command Line Interpreters Are Alike

When a command line interpreter understands a specific command, it does so based on the programming language and syntax. This means that one command that works in one situation, under a particular operating system and programming language, might not work the same way (or at all) under a different environment.

For example, one platform might use the command scannow to scan the computer for errors, but another program or operating system that doesn’t have that capability built in, might do nothing. Or, if it has a similar function, the command line interpreter might only understand scan or scantime, for example.

Syntax is important, too, because they’re sensitive to the point that any mistyping might be misinterpreted as a totally different command. For example, scannow might be what the program uses to start a scan, but if you remove the last letter, scanno might be how it understands when it should stop the scan.

More Information on Command Line Interpreters

In most Windows operating systems, the primary command line interpreter is Command Prompt. Windows PowerShell is a more advanced command line interpreter available alongside Command Prompt in more recent versions of Windows. Windows Terminal also includes command-line tools but it’s not built-in to Windows.

In Windows XP and Windows 2000, a special diagnostic tool called Recovery Console also acts as a command line interpreter to perform various troubleshooting and system repair tasks.

The command line interface on the macOS operating system is called Terminal.

Sometimes, both a command line interface and a graphical user interface are included within the same program. When this is the case, it’s typical for one interface to support certain functions that are excluded in the other. It’s usually the command line portion that includes more features because it provides raw access to the application files and isn’t limited by what the software developer chose to include in the GUI.

What is Command Line Interface (CLI)?

CLI stands for:

• Command Line Interface
• Command Line Interpreter
• Command Line Input

Command Line Input

CLI is a command line program that accepts text input to execute operating system functions.

In the 1960s, using only computer terminals, this was the only way to interact with computers.

In the 1970s an 1980s, command line input was commonly used by Unix systems and PC systems like MS-DOS and Apple DOS.

Today, with graphical user interfaces (GUI), most users never use command-line interfaces (CLI).

However, CLI is still used by software developers and system administrators to configure computers, install software, and access features that are not available in the graphical interface.

Examples

The software package manager npm uses command line input to install software:

Windows Example

Mac OS Example

You can navigate your folders (directories) with command line commands:

Windows Example

Use CLI commands with great attention.

Wrong use can easily delete files or destroy your computer system completely.

Basic Linux CLI Commands

Command	Description
ls	List the directory (folder) system.
cd pathname	Change directory (folder) in the file system.
cd ..	Move one level up (one folder) in the file system.
cp	Copy a file to another folder.
mv	Move a file to another folder.
mkdir	Creates a new directory (folder).
rmdir	Remove a directory (folder).
clear	Clears the CLI window.
exit	Closes the CLI window.
man command	Shows the manual for a given command.

Basic Windows CLI Commands

Command	Description
dir	List the directory (folder) system.
cd pathname	Change directory (folder) in the file system.
cd \	Move to the root folder of the file system.
cd ..	Move one level up (one folder) in the file system.
copy	Copy a file to another folder.
move	Move a file to another folder.
type filename	Type a file.
mkdir or md	Creates a new directory (folder).
rmdir or rd	Removes a directory (folder).
cls	Clears the CLI window.
exit	Closes the CLI window.
help command	Shows the manual for a given command.

DOS Commands Help

You can display all available commands with the help command:

Example

ASSOC	Displays or modifies file extension associations.
ATTRIB	Displays or changes file attributes.
BREAK	Sets or clears extended CTRL+C checking.
BCDEDIT	Sets properties in boot database to control boot loading.
CACLS	Displays or modifies access control lists (ACLs) of files.
CALL	Calls one batch program from another.
CD	Displays the name of or changes the current directory.
CHCP	Displays or sets the active code page number.
CHDIR	Displays the name of or changes the current directory.
CHKDSK	Checks a disk and displays a status report.
CHKNTFS	Displays or modifies the checking of disk at boot time.
CLS	Clears the screen.
CMD	Starts a new instance of the Windows command interpreter.
COLOR	Sets the default console foreground and background colors.
COMP	Compares the contents of two files or sets of files.
COMPACT	Displays or alters the compression of files on NTFS partitions.
CONVERT	Converts FAT volumes to NTFS. You cannot convert the current drive.
COPY	Copies one or more files to another location.
DATE	Displays or sets the date.
DEL	Deletes one or more files.
DIR	Displays a list of files and subdirectories in a directory.
DISKPART	Displays or configures Disk Partition properties.
DOSKEY	Edits command lines, recalls Windows commands, and creates macros.
DRIVERQUERY	Displays current device driver status and properties.
ECHO	Displays messages, or turns command echoing on or off.
ENDLOCAL	Ends localization of environment changes in a batch file.
ERASE	Deletes one or more files.
EXIT	Quits the CMD.EXE program (command interpreter).
FC	Compares two files or sets of files, and displays the differences between them.
FIND	Searches for a text string in a file or files.
FINDSTR	Searches for strings in files.
FOR	Runs a specified command for each file in a set of files.
FORMAT	Formats a disk for use with Windows.
FSUTIL	Displays or configures the file system properties.
FTYPE	Displays or modifies file types used in file extension associations.
GOTO	Directs the Windows command interpreter to a labeled line in a batch program.
GPRESULT	Displays Group Policy information for machine or user.
GRAFTABL	Enables Windows to display an extended character set in graphics mode.
HELP	Provides Help information for Windows commands.
ICACLS	Display, modify, backup, or restore ACLs for files and directories.
IF	Performs conditional processing in batch programs.
LABEL	Creates, changes, or deletes the volume label of a disk.
MD	Creates a directory.
MKDIR	Creates a directory.
MKLINK	Creates Symbolic Links and Hard Links.
MODE	Configures a system device.
MORE	Displays output one screen at a time.
MOVE	Moves one or more files from one directory to another directory.
OPENFILES	Displays files opened by remote users for a file share.
PATH	Displays or sets a search path for executable files.
PAUSE	Suspends processing of a batch file and displays a message.
POPD	Restores the previous value of the current directory saved by PUSHD.
PRINT	Prints a text file.
PROMPT	Changes the Windows command prompt.
PUSHD	Saves the current directory then changes it.
RD	Removes a directory.
RECOVER	Recovers readable information from a bad or defective disk.
REM	Records comments (remarks) in batch files or CONFIG.SYS.
REN	Renames a file or files.
RENAME	Renames a file or files.
REPLACE	Replaces files.
RMDIR	Removes a directory.
ROBOCOPY	Advanced utility to copy files and directory trees.
SET	Displays, sets, or removes Windows environment variables.
SETLOCAL	Begins localization of environment changes in a batch file.
SC	Displays or configures services (background processes).
SCHTASKS	Schedules commands and programs to run on a computer.
SHIFT	Shifts the position of replaceable parameters in batch files.
SHUTDOWN	Allows proper local or remote shutdown of machine.
SORT	Sorts input.
START	Starts a separate window to run a specified program or command.
SUBST	Associates a path with a drive letter.
SYSTEMINFO	Displays machine specific properties and configuration.
TASKLIST	Displays all currently running tasks including services.
TASKKILL	Kill or stop a running process or application.
TIME	Displays or sets the system time.
TITLE	Sets the window title for a CMD.EXE session.
TREE	Graphically displays the directory structure of a drive or path.
TYPE	Displays the contents of a text file.
VER	Displays the Windows version.
VERIFY	Tells Windows whether to verify that your files are written correctly to a disk.
VOL	Displays a disk volume label and serial number.
XCOPY	Copies files and directory trees.
WMIC	Displays WMI information inside interactive command shell.

Command Help

For more information on a specific command, type help + command-name

Example

Displays or sets the date.

Type DATE without parameters to display the current date setting and
a prompt for a new one. Press ENTER to keep the same date.

If Command Extensions are enabled the DATE command supports
the /T switch which tells the command to just output the
current date, without prompting for a new date.