Basic Shell Scripting Syntax Unix…Essentials

Just wanted to post very basic shell scripting essentials:

Basic Shell Scripting Concepts:

Arithmetic Evaluation (op refers to Operation):

let answer=var1 OP var2; echo $answer;

echo `expr var1 OP var2`

For … loop:

for file in x

do

    {body}

done

[x can be numbers, letters, paths etc]

If….then:

if  [ expression ]

then

   {body}

elif [ expression ]

then

   {body}

else

   {body}

fi

case:

case "VAR" in

   Result1)     {body}

   ;;

   Result2)    {body}

   ;;

   *)    {body}

   ;;

esac

do….while:

while  condition

do

   {body}

done

until…..do:

until condition
do
   {body}
done