CentOS / RHEL: Install KornShell (KSH)


am porting ksh script from Sun/Oracle Unix to Linux. How do I install ksh (KornShell) in CentOS / Fedora / Red Hat Enterprise Linux? How do I run and test ksh script on RHEL/CentOS Linux?


KSH was developed by David Korn at Bell Labs in 1980s. KSH is is quite popular is quite loved by sysadmins to automate everyday tasks on Unix like operating systems. You can install ksh on CentOS / RHEL. KSH-93 is the most recent version of the KornShell. It is a shell programming language, which is upward compatible with “sh” (the Bourne Shell).

Steps to install ksh in Linux

Open the Terminal app.

Type the ‘yum install ksh‘ command on CentOS/RHEL.

Type the ‘dnf install ksh‘ command on Fedora Linux.

Update your shell in /etc/passwd

Start using your ksh shell.

Let us see steps in detailed to install KornShell (KSH) on a RHEL/CentOS Linux based system.

How to install the Korn Shell (KSH)

Open a terminal and then type the following yum command to install the ksh shell:

$ sudo yum install ksh



# yum install ksh


Sample outputs:

Loaded plugins: auto-update-debuginfo, protectbase, rhnplugin, security

This system is receiving updates from RHN Classic or RHN Satellite.

0 packages excluded due to repository protections

Setting up Install Process

Resolving Dependencies

–> Running transaction check

—> Package ksh.x86_64 0:20100621-19.el6_4.4 will be installed

–> Finished Dependency Resolution


Dependencies Resolved



Package  Arch        Version                   Repository                 Size



ksh      x86_64      20100621-19.el6_4.4       rhel-x86_64-server-6      687 k


Transaction Summary


Install       1 Package(s)


Total download size: 687 k

Installed size: 0

Is this ok [y/N]: y

Downloading Packages:

ksh-20100621-19.el6_4.4.x86_64.rpm                       | 687 kB     00:00

Running rpm_check_debug

Running Transaction Test

Transaction Test Succeeded

Running Transaction

Installing : ksh-20100621-19.el6_4.4.x86_64                               1/1

Verifying  : ksh-20100621-19.el6_4.4.x86_64                               1/1



ksh.x86_64 0:20100621-19.el6_4.4



A note about Fedora Linux users

Type the following command to install ksh on Fedora Linux:

$ sudo dnf install ksh

How can I find out path for ksh shell?

To find out path to the ksh, type:

$ whereis ksh


OR use the grep command as follows:

$ grep –color ksh /etc/shells


Sample outputs:

Fig.01: Finding ksh path


/bin/ksh is now added to list of acceptable shells, verify it with the cat command:

$ cat /etc/shells


Sample outputs:







How do I set ksh as a default shell?

The superuser (root) may change the login shell for any account using any one of the following syntax:

$ sudo chsh -s /bin/ksh UserNameHere



# chsh -s /bin/ksh UserNameHere


In this example, set default login shell to /bin/ksh for nixcraft user:

# chsh -s /bin/ksh nixcraft


Regular user can type the following command to change their shell to the ksh:

$ chsh -s /bin/ksh


Logout and login again. Verify your shell with the following command:

$ echo $SHELL


Sample outputs:


To see ksh version, type:

$ ksh –version


Sample outputs:

version         sh (AT&T Research) 93t+ 2010-06-21

Sample ksh program

Create a file called test.ksh using a text editor:


# Name: test.ksh

# Purpose: My first ksh script

# Author: nixCraft <www.cyberciti.biz> under GPL v2.x+

# ————————————————————————

# set variables

FILE= /etc/passwd

NOW= $(date)

HOSTNAME= hostname



# Greet user

print  Hi, $USER. I m $0. I m $SHELL script running on $HOSTNAME at $NOW.


print  *** User accounts: $USERS_ACCOUNT

print  *** Current working directory: $PWD


print  *** Running for loop test just for fun:

for x in {1..3}


print  Welcome $x times.


Save and close the file. Run it as follows:

chmod +x test.sh


Sample outputs:

Fig.02 Ksh script in action.

See also:

Debian / Ubuntu Linux: Install KSH

See man pages for more info ksh(1),grep(1),whereis(1)



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