Open In App

Difference between Thompson Shell and POSIX Shell

Last Updated : 24 Apr, 2023
Like Article

Introduction :

Thompson Shell, also known as sh, was the first Unix shell created by Ken Thompson in the early 1970s. It was designed to be a small, simple, and fast shell with a limited number of features. The Thompson Shell is no longer in use today and has been replaced by more advanced shells such as the POSIX Shell.

The POSIX Shell, also known as sh, is a standard Unix shell that conforms to the POSIX (Portable Operating System Interface) standard. It is a more advanced shell compared to the Thompson Shell and provides a wide range of features, including command history, job control, and shell scripting. The POSIX Shell is the default shell for most Unix-based systems and is still widely used today.

1. Thompson Shell : Thompson Shell is the first Unix shell which was introduced by Ken Thompson. It was a simple command interpreter which introduced several innovative features to the command-line interface. This command shell led to the development of the later Unix Command shells. It was not designed for scripting. It was developed at AT&T Bell Laboratories. It was released in 1971.

 2. POSIX Shell : POSIX Shell is a command line shell for computer operating system which was introduced by IEEE Computer Society. POSIX stands for Portable Operating System Interface. POSIX Shell is based on the standard defined in Portable Operating System Interface (POSIX) – IEEE P1003.2. It is considered as one of the primary shell in scripts. It was released in 1992. 
Difference between Thompson Shell and POSIX Shell :

1. It was developed by Ken Thompson at AT&T Bell Laboratories. It was developed by IEEE Computer Society.
2. It was released in 1971. It was released in 1992.
3. It is the first Unix shell. It is one of the primary shell.
4. Its usual environment is Unix. It usual environment is POSIX.
5. It does not have license. It has IEEE standard license.
6. It does not have unicode support. It current version has unicode support.
7. It does not have stream redirection. It has stream redirection for arbitrary fds.
8. It is used as command line interpreter only. It is used as command line interpreter as well as scripting language.
9. It does not have command history. It current version has command history.
10. It does not have value prompt. It has value prompt.
11. Created by Ken Thompson Provides more features
12. Small, simple, and fast Command history
13. Limited number of features Job control
14. No longer in use  Default shell for most Unix-based systems
15. Basic shell  Shell scripting support

Similar Reads

Shell Script to Show the Difference Between echo “$SHELL” and echo ‘$SHELL’
In shell scripting and Linux, the echo command is used to display text on the terminal or console. When used with the $SHELL variable, which contains the path of the current user's shell program, the output of the echo command can be different depending on whether the variable is enclosed in single or double quotes. echo "$SHELL" will expand the $S
4 min read
Shell Scripting - Difference between Korn Shell and Bash shell
Korn Shell: Korn Shell or KSH was developed by a person named David Korn, which attempts to integrate the features of other shells like C shell, Bourne Shell, etc. Korn Shell allows developers to generate and create new shell commands whenever it is required. Korn shell was developed a long year back as it is older than the BASH shell and it has fe
3 min read
Difference Between Bind Shell and Reverse Shell
A shell is a program that interprets our commands and gives the written commands to the operating system. It acts as an interface between the user and the operating system. It takes input from the keyboard and gives it to the OS, and the terminal lets you type commands and interact with the shell. Some Popular Shell: Windows PowerShellWindows Comma
3 min read
Korn Shell vs Bash Shell
Introduction : Korn Shell, also known as ksh, is a Unix shell that was developed by David Korn in the early 1980s. It was designed to be a more powerful and interactive shell than the Bourne Shell (sh), which was the standard Unix shell at the time. The Korn Shell has features such as command-line editing, job control, and shell scripting, making i
6 min read
Difference Between Single and Double Quotes in Shell Script and Linux
Single quotes and double quotes are both functional in Linux while working with shell scripts or executing commands directly in the terminal but there is a difference between the way the bash shell interprets them. Single quotes: Enclosing characters in single quotation marks (') holds onto the literal value of each character within the quotes. In
3 min read
Difference between Shell and Kernel
Introduction : In a computer operating system, the shell and the kernel are two important components that work together to enable the user to interact with the system. The shell is a command-line interface that allows the user to enter commands to interact with the operating system. It acts as an intermediary between the user and the kernel, interp
3 min read
Bash Script - Difference between Bash Script and Shell Script
In computer programming, a script is defined as a sequence of instructions that is executed by another program. A shell is a command-line interpreter of Linux which provides an interface between the user and the kernel system and executes a sequence of instructions called commands. A shell is capable of running a script. A script that is passed to
3 min read
Difference between Difference Engine and Analytical Engine
Introduction: The development of computing technology has a rich history, with many inventions and innovations leading to the creation of the modern computer. Two such machines, the Difference Engine and Analytical Engine, were created by the English mathematician and inventor Charles Babbage in the 19th century. While these machines share some sim
7 min read
Difference between Voltage Drop and Potential Difference
Voltage Drop is defined as the decrease in the electric potential along the path of current that is flowing in an electric circuit. Voltage drop can be assigned at each point in the electric circuit that is proportional to the electrical elevation. The amount of energy delivered per second to any component in the circuit is equal to the voltage dro
4 min read
Difference Between Electric Potential and Potential Difference
The flow of electric charges is known as electricity, and it is responsible for producing electric current. An important word associated with electricity is electric potential. A potential difference is required to create the flow of electrons and hence, produce electricity. Before understanding the difference between electric potential and potenti
7 min read