ch10.txt

平时学习linux总结的命令

Chapter 10

----------
while Loop
----------
declare raining="1"
while [ "$raining" -eq "1" ]
    do
        echo "Still raining."
done

-------------------------------
Menu Program Using a while Loop
-------------------------------
#!/bin/bash
declare flag="1"
while [ "$flag" -eq "1" ]
   do
             clear
             echo " " 
             echo "The Telephone Book "
             echo " "
             echo "1. Display A Telephone Number "
             echo "2. Add A New Telephone Number "
             echo " "
             echo "Q Quit "
             echo " "
             echo "Enter your selection: "
             echo " "
             read selection 
             case $selection  in		 "1")
                          #Run the subprogram to display a phone number
                          getnum
                          ;;
                   "2")
                          #Run the subprogram to add a new phone number
                          addnum
                          ;;
                    "q")
                          flag=0
                          ;;
                    "Q")
                          flag=0
                          ;;
                    *)
                          echo "You made an invalid selection. Try again."
             esac
done

------------------
while Loop Counter
------------------
declare counter=0
while [ "$counter" -lt 1000 ]
do
  let counter="$counter + 1"
done

-----------------
Nested while Loop
-----------------
clear
declare counter1=1
declare counter2

while [ "$counter1" -lt 6 ]
    do
               echo "Warning: There's a bug in your program."
       set counter2=1
               while [ "$counter2" -lt 200 ]
            do
               let counter2="$counter2 + 1"
          done
    clear
          let counter2=1
           while [ "$counter2" -lt 200 ]
              do
                  let counter2="$counter2 + 1"
            done
           let counter1="$counter1 + 1"
done

------------------
Endless while Loop
------------------
declare raining="0"
while [ "$raining" -eq "1" ]
    do
            echo "Still raining."
done

----------------------------
while Loop in a Menu Program
----------------------------
#!/bin/bash
declare raining="1"
while [ "$raining" -eq "1" ]
   do
             clear
             echo " "
             echo "Is it raining? "
             echo " "
             echo "1. Yes "
             echo "2. No "
             echo " "
             echo "Enter your selection: "
             read raining 
done
echo "It stopped raining."