Shell Script to display current date, calendar, and the number of user logged

in Categories Academic last updated April 3, 2008

This script use the concept of command substitution. It allows allows the output of a command to replace the command name. There are two forms:

$(command)

or

`command`

Bash shell performs the expansion by executing command and replacing the command substitution with the standard output of the command, with any trailing newlines deleted. Embedded newlines are not deleted, but they may be removed during word splitting.

For example you can execute date command to display todays date and then set a variable called NOW:
NOW=$(date)
or
NOW=`date`
To display back variable value simply run echo command:
echo $NOW

Sample Shell Script

#!/bin/bash
# Shell script to display current date, calendar, and the number of
# user logged.
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
echo "Today is $(date)"
echo ""
 
echo "Calendar :"
cal
 
echo "Number of users currently logged : $(who | wc -l)"

Shell Script to ask user his / her name and then display it with a G’Day/Good morning message

in Categories Academic last updated April 3, 2008

This script greets user with a message. Then it displays prompt asking user her name. Once name entered it will display Gooday message using echo command.

read statement will read one line from the user (keyboard) or from file and store it to a variable called yourname.

#!/bin/bash
# Shell Script to ask user his/her name and then display it with a
# GoodDay/Good morning message
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
 
echo "Hi! I'm $(hostname) computer!!"
echo -n "May I know your name please ? "
read yourname
echo "Goo Day $yourname"

Script to Store given command and execute them

in Categories Academic last updated April 3, 2008

Write script to store the following command and execute them:
a) date
b) echo “Message”
c) cal

#!/bin/bash
# Script to Store given command and execute them
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
date
cal
echo "Hello Friends"

Shell script to find the number of files present in the current directory without using WC command

in Categories Academic last updated October 14, 2009
#!/bin/bash
# Shell script to find the number of files present in the current
# directory without using WC command.
# NOTE/TIP:
# If allowed to use WC command then it should be as follows:
# ls | wc -l
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
FILE="/tmp/count.txt"
 
echo -n "Enter directory name : "
read dname
 
ls $dname > $FILE
 
echo "No of files in directory : $(grep [^*$] $FILE -c)"
rm -f $FILE

Shell Script To Display The Text Entered By The User in Bold

in Categories Academic last updated April 15, 2008

Write a shell script to display the text entered by the user in bold?

You need to use the tput utility to display text in bold. It uses the terminfo database to make the values of terminal-dependent capabilities and information available to the shell, to initialize or reset the terminal, or return the long name of the requested terminal type. tput bold turns on bold (extra bright) mode.

#!/bin/bash
# Script to display the text entered by the user in bold
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http:>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
# read man page of tput command.
echo -n "Enter text : "
read text
echo "Here is what you entered "
# use tput command to display it in bold
tput bold
echo "$text"
echo -n "Press any key to continue..."
# okay turn of bold effect
read key
# it will clear screen too
tput reset