Sunday, April 9, 2017

Shell Scripting Tutorial for Beginners 20 - FOR loop to execute commands



#!/bin/bash
# for loops

echo "all the files in directory--------"
for item in *
do  
   if [ -f $item ]
   then 
     echo $item
   fi
done

echo
echo "all the directory in directory--------"
for item in *
do  
   if [ -d $item ]
   then 
     echo $item
   fi
done
echo
echo "execute list of commands--------"
for command in ls pwd date
do  
     echo "command name -> $command"
     $command
done

Shell Scripting Tutorial for Beginners 18 - FOR loop



Basic Syntax:



for VARIABLE in 1 2 3 4 5 .. N
do
 command1
 command2
 commandN
done
#OR-----------------------------------------------

for VARIABLE in file1 file2 file3
do
 command1 on $VARIABLE
 command2
 commandN
done
#OR-----------------------------------------------

for OUTPUT in $(Linux-Or-Unix-Command-Here)
do
 command1 on $OUTPUT
 command2 on $OUTPUT
 commandN
done
#OR-----------------------------------------------
for (( EXP1; EXP2; EXP3 ))
do
 command1
 command2
 command3
done




Example:



#!/bin/bash
# for loops
#Example 1 ------------------------
for i in 1 2 3 4 5
do
   echo $i
done

#Example 2 ------------------------
for i in {0..10}
do
   echo $i
done

#Example 3 ------------------------
for i in {0..10..2}
do
   echo $i
done

#Example 4 ------------------------
echo ${BASH_VERSION}
for (( i=0; i<5; i++ ))
do
   echo $i
done

Saturday, April 1, 2017

Shell Scripting Tutorial for Beginners 18 - UNTIL loop



#!/bin/bash
# until loops
n=1

# first way
echo "----until loops------first way-------------------"
until [ $n -gt 10 ]
do
    echo "$n"
    (( n++ ))
done


# second way
n=1
echo "----until loops------second way-------------------"
until (( $n > 10 ))  
do
    echo "$n"
    (( ++n ))
done

# third way
n=1
echo "----until loops------third way-------------------"
until [ $n -gt 10 ]
do
    echo "$n"
    n=$(( n+1 ))
done
output


test@test:~/Desktop$ ./hello.sh 
----until loops------first way-------------------
1
2
3
4
5
6
7
8
9
10
----until loops------second way-------------------
1
2
3
4
5
6
7
8
9
10
----until loops------third way-------------------
1
2
3
4
5
6
7
8
9
10
test@test:~/Desktop$ 

Shell Scripting Tutorial for Beginners 16 - using sleep and open termina...



#!/bin/bash
# while loops
n=1

while [ $n -le 3 ]
do
    echo "$n"
    (( n++ ))
    gnome-terminal &
done

Shell Scripting Tutorial for Beginners 15 - WHILE Loops


#!/bin/bash
# while loops
n=1

# first way
echo "----while loops------first way-------------------"
while [ $n -le 10 ]
do
    echo "$n"
    (( n++ ))
done


# second way
n=1
echo "----while loops------second way-------------------"
while (( $n <= 10 ))  
do
    echo "$n"
    (( ++n ))
done

# third way
n=1
echo "----while loops------third way-------------------"
while [ $n -le 10 ]
do
    echo "$n"
    n=$(( n+1 ))
done
output:
test@test:~/Desktop$ ./hello.sh 
----while loops------first way-------------------
1
2
3
4
5
6
7
8
9
10
----while loops------second way-------------------
1
2
3
4
5
6
7
8
9
10
----while loops------third way-------------------
1
2
3
4
5
6
7
8
9
10
test@test:~/Desktop$ 

Saturday, March 25, 2017

Shell Scripting Tutorial for Beginners 14 - Array variables

#! /bin/bash

os=('ubuntu' 'windows' 'kali')
os[6]='mac'

unset os[2]
echo "${os[@]}"
echo "${os[0]}"
echo "${!os[@]}"
echo "${#os[@]}"

string=dasfdsafsadfasdf
echo "${string[@]}"
echo "${string[0]}"
echo "${string[1]}"
echo "${#string[@]}"

Wednesday, March 22, 2017

Shell Scripting Tutorial for Beginners 13 - The case statement Example



#! /bin/bash

echo -e "Enter some character : \c"
read value


case $value in
    [a-z] )
        echo "User entered $value a to z" ;;
    [A-Z] )
        echo "User entered $value A to Z" ;;
    [0-9] )
        echo "User entered $value 0 to 9" ;;
    ? )
        echo "User entered $value special character" ;;
    * )
        echo "Unknown input" ;;
esac
Output:


test@test$ ./hello.sh 
Enter some character : f
User entered f a to z
test@test$ ./hello.sh 
Enter some character : K
User entered K a to z
test@test$ LANG=C
test@test$ ./hello.sh 
Enter some character : K
User entered K A to Z
test@test$ ./hello.sh 
Enter some character : 9
User entered 9 0 to 9
test@test$ ./hello.sh 
Enter some character : 5
User entered 5 0 to 9
test@test$ ./hello.sh 
Enter some character : &
User entered & special character
test@test$ ./hello.sh 
Enter some character : sdsdsdsd
Unknown input
test@test$ 

Tuesday, March 21, 2017

Shell Scripting Tutorial for Beginners 12 - The case statement

#! /bin/bash

vehicle=$1

case $vehicle in
    "car" )
        echo "Rent of $vehicle is 100 dollar" ;;
    "van" )
        echo "Rent of $vehicle is 80 dollar" ;;
    "bicycle" )
        echo "Rent of $vehicle is 5 dollar" ;;
    "truck" )
        echo "Rent of $vehicle is 150 dollar" ;;
    * )
        echo "Unknown vehicle" ;;
esac

Saturday, March 18, 2017

Shell Scripting Tutorial for Beginners 11 - Floating point math operatio...



#! /bin/bash

num1=20.5
num2=5

echo "$num1+$num2" | bc
echo "$num1-$num2" | bc
echo "20.5*5" | bc
echo "scale=20;20.5/5" | bc
echo "20.5%5" | bc

num=4

echo "scale=2;sqrt($num)" | bc -l
echo "scale=2;3^3" | bc -l