shell script (constructs)

if...else...fi

num1=1 num11="1" num2=2 num22="2" #if...else...fi echo "if...else...fi" echo     #value     if [ $num1 -eq $num11 ]; then         echo "int equal"     else         echo "int not equal"     fi     echo     #string     if [ ${num11} == ${num22}  ];  then         echo "str equal"     else         echo "str not equal"     fi     echo

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for...done

#for...done echo "for...done" echo     #string     for animal in dog cat elephant     do         echo "there are ${animal}s";     done     echo     #value     for val in 1 2 3     do         echo `expr 2 \* $val`     done     #value2     s=0     for (( i=1; i<=2; i=i+1 ))     do         s=$(($s+$i))     done     echo "The result of '1+2+3+...+$nu' is ==> $s"

while...do....done

#while...do...done echo "while...do...done" wh_val=5 while [ $wh_val -ne 0 ]; do     echo "$wh_val"     wh_val=`expr $wh_val - 1` done

case...esac

#case ..... esac ary_fruit=("Apple" "Banana" "Guava") for loc in 0 1 2 do     case ${ary_fruit[$loc]} in         "Apple")             echo this fruit is ${ary_fruit[$loc]}             ;;         "Banana")             echo this fruit is ${ary_fruit[$loc]}             ;;         "Guava")             echo this fruit is ${ary_fruit[$loc]}             ;;     esac done

result

steven@ATM64:~/base_shell$ sh constructs.sh if...else...fi int equal str not equal for...done there are dogs there are cats there are elephants 2 4 6 The result of '1+2+3+...+' is ==> 3 while...do...done 5 4 3 2 1 this fruit is Apple this fruit is Banana this fruit is Guava

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