CentOS / RHEL: Install KornShell (KSH)
I
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
OR
# 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
================================================================================
Installing:
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
Installed:
ksh.x86_64 0:20100621-19.el6_4.4
Complete!
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:
/bin/bash
/bin/csh
/bin/ksh
/bin/sh
/bin/tcsh
/bin/zsh
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
OR
# 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:
/bin/ksh
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:
#!/bin/ksh
# 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
USERS_ACCOUNT= $(wc -l $FILE)
# 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}
do
print Welcome $x times.
done
Save and close the file. Run it as follows:
chmod +x test.sh
./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)
