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 it a popular choice for both interactive use and scripting.

Bash, short for Bourne-Again SHell, is a Unix shell that was developed by Brian Fox for the GNU Project in the late 1980s. Bash is a free and open-source shell that is widely used on Linux and other Unix-like systems. It is compatible with the Bourne Shell and includes features such as command-line editing, job control, and shell scripting. Bash has become the default shell for many Linux distributions and is the most widely used shell today.

Both Korn Shell and Bash are powerful and popular Unix shells that provide similar features and capabilities. They are both capable of running scripts written for the Bourne Shell, and both support interactive use and shell scripting. However, Bash has become more popular in recent years due to its widespread use on Linux systems and its compatibility with the Bourne Shell.

Korn Shell was developed in Bell Labs by David Korn and the year was 1980. But it was announced later at USENIX on 14th July 1983. The Korn shell has most of the features which one can be found in the bourne shell as well as the c shell. The extension of the Korn shell is .ksh. It provides better performance in terms of the execution of any scripts or commands. We can locate the Korn shell in /bin/kash.      

Features of Korn shell (ksh):

• Job Control: Korn shell provides extensive support for job control, which allows you to manage and manipulate running processes.
• Advanced I/O Redirection: Korn shell allows you to perform advanced I/O redirection, such as redirecting output to a file while still displaying it on the screen.
• Command Line Editing: Korn shell provides command line editing features that allow you to edit and modify previously entered commands.
• Arithmetic Evaluation: Korn shell has built-in support for arithmetic evaluation, allowing you to perform mathematical calculations directly within the shell.
• Variables: Korn shell supports variables and parameter expansion, which allow you to manipulate and modify variables within the shell.          

Bash Shell is a Unix shell that was developed by Brian Fox. The Bash shell stands for ‘Bourne-Again shell’. This was first released in the year 1989. For most Linux distributions, it is used as the default login shell. We can use the bash shell for reading or executing any command. The basic feature of the bash shell is all taken from sh. There are also different features like history which are copied from csh and ksh. 

Features of Bash shell (bash):

• Command Line Editing: Bash shell provides powerful command line editing features, including history, tab completion, and Emacs and Vi editing modes.
• Programmable Completion: Bash shell allows you to define custom completion functions for commands and arguments, making it easier to navigate and use complex commands.
• Process Substitution: Bash shell provides support for process substitution, which allows you to treat the output of a command as if it were a file.
• Brace Expansion: Bash shell provides support for brace expansion, which allows you to generate multiple file names or command arguments with a single command.
• Shell Functions: Bash shell supports shell functions, which allow you to define and call custom functions within the shell.

Here are a few key differences:

• Korn shell is older than Bash shell: Korn shell was developed in the 1980s, while Bash shell was developed in the 1990s. As a result, Korn shell is more widely used in older systems, while Bash shell is more common in modern systems.
• Syntax: Both shells have a similar syntax and share many of the same commands. However, there are some differences in syntax, such as the way arrays are declared and indexed.
• Features: Bash shell has more features than Korn shell, including command line editing, history, and tab completion. It also has more advanced programming features such as regular expressions and process substitution.
• Compatibility: Bash shell is backward compatible with the Bourne shell (sh), which means that scripts written for sh can be run with bash without modification. Korn shell is not fully compatible with sh, which means that some sh scripts may need to be modified to run on ksh.

Following is a table of differences between Korn Shell and Bash Shell:

	Korn Shell	Bash Shell
1.	The extension of the Korn shell is .ksh.	The extension of the bash shell is .sh.
2.	In the Korn shell, we use the print command for printing any output.	In Bash shell, we use the command name echo printing any output.
3.	The Korn shell can be found in  /bin/ksh.	We can find the bash shell in /bin/bash.
4.	In terms of the execution of commands and scripts, the Korn shell is much better.	In terms of the execution of commands and scripts, the performance is not like the Korn shell.
5.	As they have old syntax, the scripts of the Korn shell are less readable.	As they have the new syntax, the scripts of the bash shell are more readable.
6.	The programming features provided by the Korn shell are much better than the bash shell.	The programming feature provided by the bash shell is not better than the Korn shell.
7.	Developed by David Korn in the early 1980s	Developed by Brian Fox for the GNU Project in the late 1980s
8.	Designed to be a more powerful and interactive shell than the Bourne Shell	A free and open-source shell widely used on Linux and other Unix-like systems
9.	Supports command-line editing, job control, and shell scripting	Supports command-line editing, job control, and shell scripting
10	Compatible with the Bourne Shell	Compatible with the Bourne Shell
11	Provides various types of arrays	Provides arrays and associative arrays
12	Uses a different syntax for arithmetic operations	Uses a similar syntax for arithmetic operations
13	Supports floating-point arithmetic	Supports floating-point arithmetic
14	Has a more compact syntax for command substitution	Has a more verbose syntax for command substitution
15	Generally faster than Bash	Generally slower than Korn Shell