sample scripts

venkateshkumar — Fri, 13 Mar 2009 07:07:50 +0000

# shell script that will add two nos, which are supplied as command line argument,
# and if this two nos are not given show error and its usage

#!/bin/bash

if [ $# -ne 2 ]
then
    echo "Usage - $0   x    y"
    echo "        Where x and y are two nos for which I will print sum"
    exit 1
fi
    echo "Sum of $1 and $2 is `expr $1 + $2`"

—————————————————————————————————————–

# Q2. Script to find out bigest number
#!/bin/bash
#
# Algo:
#      1) START: Take three nos as n1,n2,n3.
#      2) Is n1 is greater than n2 and n3, if yes 
#         print n1 is bigest no goto step 5, otherwise goto next step
#      3) Is n2 is greater than n1 and n3, if yes 
#         print n2 is bigest no goto step 5, otherwise goto next step
#      4) Is n3 is greater than n1 and n2, if yes 
#         print n3 is bigest no goto step 5, otherwise goto next step
#      5) END
#
    if [ $# -ne 3 ]
    then
        echo "$0: number1 number2 number3 are not given" >&2
        exit 1    
    fi
    n1=$1
    n2=$2
    n3=$3
    if [ $n1 -gt $n2 ] && [ $n1 -gt $n3 ]
    then
        echo "$n1 is Bigest number"
    elif [ $n2 -gt $n1 ] && [ $n2 -gt $n3 ]         
    then
        echo "$n2 is Bigest number"
    elif [ $n3 -gt $n1 ] && [ $n3 -gt $n2 ]         
    then
        echo "$n3 is Bigest number"
    elif [ $1 -eq $2 ] && [ $1 -eq $3 ] && [ $2 -eq $3 ]
    then
        echo "All the three numbers are equal"    
    else
        echo "I can not figure out which number is biger"    
    fi    

-------------------------------------------------------------------- -----------------------------------------------

#script to print given number in reverse order, for eg. If no is 123 it must print as 321.

#!/bin/bash
# Script to reverse given no
# Alg:
#       1) Input number n
#       2) Set rev=0, sd=0
#       3) Find single digit in sd as n % 10 it will give (left most digit)
#       4) Construct revrse no as rev * 10 + sd
#       5) Decrment n by 1
#       6) Is n is greater than zero, if yes goto step 3, otherwise next step
#       7) Print rev
#
if [ $# -ne 1 ]
then
    echo "Usage: $0   number"
    echo "       I will find reverse of given number"
    echo "       For eg. $0 123, I will print 321"
    exit 1
fi

n=$1
rev=0
sd=0

while [ $n -gt 0 ]
do
    sd=`expr $n % 10`
    rev=`expr $rev \* 10  + $sd`
    n=`expr $n / 10`
done
    echo  "Reverse number is $rev"
---------------------------------------------------------------- ------------------------------------------------------------

#script to print given numbers sum of all digit, For eg. If no is 123 it's sum of all digit will be 1+2+3 = 6.

#!/bin/bash
# Alg:
#       1) Input number n
#       2) Set sum=0, sd=0
#       3) Find single digit in sd as n % 10 it will give (left most digit)
#       4) Construct sum no as sum=sum+sd
#       5) Decrment n by 1
#       6) Is n is greater than zero, if yes goto step 3, otherwise next step
#       7) Print sum
#
if [ $# -ne 1 ]
then
    echo "Usage: $0   number"
    echo "       I will find sum of all digit for given number"
    echo "       For eg. $0 123, I will print 6 as sum of all digit (1+2+3)"
    exit 1
fi

n=$1
sum=0
sd=0
while [ $n -gt 0 ]
do
    sd=`expr $n % 10`
    sum=`expr $sum + $sd`
    n=`expr $n / 10`
done
    echo  "Sum of digit for numner is $sum"
    
---------------------------------------------------------------------- -----------------------------------------
#script to add real numbers:
#!/bin/bash

a=5.66
b=8.67
c=`echo $a + $b | bc`
echo "$a + $b = $c"

---------------------------------------------------------------- 
# Script to check whether "/*" is included, in $1 or not
# !/bin/bash
cat "$1" > /tmp/file.$$   2>/tmp/file0.$$
grep "*"  /tmp/file.$$    >/tmp/file0.$$

if [ $? -eq 1 ]
then
    echo "Required i.e. $1/*"
else
    echo "Symbol is Not required"    
fi    

rm -f /tmp/file.$$
rm -f /tmp/file0.$$
---------------------------------------------- --------------------------------------------------------
#script to implement getopts statement, script should understand following command line argument 
#!/bin/bash

# Q14
# -c clear
# -d dir
# -m mc
# -e vi { editor }
# Function to clear the screen
#
cls()
{
    clear
    echo "Clear screen, press a key . . ."
    read
    return
}

#
# Function to show files in current directory 
#
show_ls()
{   
    ls
    echo "list files, press a key . . ."
    read
    return
}

#
# Function to start mc
#
start_mc()
{
    if which mc > /dev/null ; then
        mc
        echo "Midnight commander, Press a key . . ."
        read
    else
        echo "Error: Midnight commander not installed, Press a key . . ."
        read
    fi          
    return
}

#
# Function to start editor 
#
start_ed()
{
    ced=$1
    if which $ced > /dev/null ; then
        $ced
        echo "$ced, Press a key . . ."
        read
    else
        echo "Error: $ced is not installed or no such editor exist, Press a key . . ."
        read
    fi          
    return
}

#
# Function to print help
#
print_help_uu()
{
           echo "Usage: $0 -c -d -m -v {editor name}"; 
           echo "Where -c clear the screen";
           echo "      -d show dir";
           echo "      -m start midnight commander shell";
           echo "      -e {editor}, start {editor} of your choice";
           return
}

#
# Main procedure start here
#
# Check for sufficent args
#

if [ $# -eq 0 ] ; then
    print_help_uu
    exit 1
fi    

#
# Now parse command line arguments
#
while getopts cdme: opt
do
    case "$opt" in
        c) cls;;
        d) show_ls;;
        m) start_mc;;
        e) thised="$OPTARG"; start_ed $thised ;;
        \?) print_help_uu; exit 1;; 
    esac
done    
--------------------------------------------------------------------------------------------------------------------
#script to use dialog box utility
temph=`date | cut -c12-13`
dat=`date +"%A %d in %B of %Y (%r)"`

if [ $temph -lt 12 ]
then
    mess="Good Morning $LOGNAME, Have nice day!"
fi

if [ $temph -gt 12 -a $temph -le 16 ]
then
    mess="Good Afternoon $LOGNAME"
fi

if [ $temph -gt 16 -a $temph -le 18 ]
then
    mess="Good Evening $LOGNAME"
fi

if which dialog > /dev/null
then
    dialog --backtitle "Linux Shell Script Tutorial"\
    --title "(-: Welcome to Linux  "\
    --infobox "\n$mess\nThis is $dat" 6 60
    echo -n "                            Press a key to continue. . .                        "
    read
    clear
else
    echo -e "$mess\nThis is $dat"
fi
------------------------------------------ ------------------------------------------------------------
# echo command with escape sequance to give differnt effects
#
# Syntax: echo -e "escape-code your message, var1, var2 etc"
# For eg. echo -e "33[1m  Hello World"
#                   |         |
#                   |         | 
#               Escape code   Message
#

clear 
echo -e "33[1m Hello World"
 # bold effect
echo -e "33[5m Blink"
       # blink effect
echo -e "33[0m Hello World"
 # back to noraml

echo -e "33[31m Hello World"
 # Red color
echo -e "33[32m Hello World"
 # Green color
echo -e "33[33m Hello World"
 # See remaing on screen
echo -e "33[34m Hello World"
echo -e "33[35m Hello World"
echo -e "33[36m Hello World"

echo -e -n "33[0m "
  # back to noraml

echo -e "33[41m Hello World"
echo -e "33[42m Hello World"
echo -e "33[43m Hello World"
echo -e "33[44m Hello World"
echo -e "33[45m Hello World"
echo -e "33[46m Hello World"

echo -e "33[0m Hello World"
  # back to noraml

sum of all digit

venkateshkumar — Wed, 11 Mar 2009 07:06:34 +0000

if [ $# -ne 1 ]
then
echo “Usage: $0 number”
echo ” I will find sum of all digit for given number”
echo ” For eg. $0 123, I will print 6 as sum of all digit (1+2+3)”
exit 1
fi

n=$1
sum=0
d=0
while [ $n -gt 0 ]
do
d=`expr $n % 10`
sum=`expr $sum + $d`
n=`expr $n / 10`
done
echo “Sum of digit for number is $sum”

Simple Calculator program

venkateshkumar — Tue, 20 Jan 2009 05:07:11 +0000

clear
echo -e “\t\t\t\t\tSimple Calculator”
echo “enter your choice”
echo “—————–”
echo “1 – Addition”
echo “2 – subtraction”
echo “3 – multiplication”
echo “4 – divison”
echo “5 – modulation”
echo “Enter the choice[1 2 3 4 5]“
read choice

#addition
if [ $choice -eq 1 ]
then
echo “enter the Ist value:”
read a1
echo “enter the IInd value:”
read a2
echo “The Result is: `expr $a1 + $a2`”
fi

#subtraction
if [ $choice -eq 2 ]
then
echo “enter the Ist value:”
read a1
echo “enter the IInd value:”
read a2
echo “The Result is: `expr $a1 – $a2`”
fi

#multiplication
if [ $choice -eq 3 ]
then
echo “enter the Ist value:”
read a1
echo “enter the IInd value:”
read a2
echo “The Result is: `expr $a1 \* $a2`”
fi

#divison
if [ $choice -eq 4 ]
then
echo “enter the Ist value:”
read a1
echo “enter the IInd value:”
read a2
echo “The Result is: `expr $a1 / $a2`”
fi

#mod
if [ $choice -eq 5 ]
then
echo “enter the Ist value:”
read a1
echo “enter the IInd value:”
read a2
echo “The Result is: `expr $a1 % $a2`”
else
#fi
#if [ $choice -gt 5 ]
#then
echo “Please, Enter the right number “
fi
exit $?

Hello world!

venkateshkumar — Sun, 14 Dec 2008 08:42:09 +0000

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sample scripts

sum of all digit

Simple Calculator program

Hello world!