Command Line Glossary

This glossary defines terms commonly used by or associated with the command line interface (CLI).

Argument - Data passed to a command for processing. File paths are a common argument.

Bash - The Bourne Again SHell is a POSIX compliant shell used to interact with the underlying operating system.

Command - Any program, script, or shell built-in that is accessible from the command line interface.

Command Line Interface (CLI) - A text-based terminal for interacting with programs and the underlying operating system.

​​Flag - See Option

Minus - The minus character [ - ] is used in Linux to specify options for commands. For example ls -l

​​Option - Use to changed the behavior of a command. Command options are often specified using a minus in Linux and a forward-slash in Windows.

Parameter - See Argument

Pipe - The pipe character [ | ] is used in Windows and Linux to redirect the output of one command into another command.

POSIX - The Portable Operating System Interface (POSIX) is a set of standards used to enable operating system interoperability.

Redirect - Rerouting of stdout and or stderr to a file rather than the screen.

stderr - See Standard Error

stdin - See Standard In

stdout - See Standard Out

Standard Error - Error and warning information that is output from a command and typically displayed to the screen.

Standard In - Input from the keyboard or other source that is provided to the shell or a command.

Standard Out - Output from a command that is typically displayed to the screen.

Switch - See Option

Tac/Tack - See Minus