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DA155 Lab. 5
Name: _____________________________ Here is a table of some of the common interrupts:
Create the script as file lab5a.sh in your bin directory #!/bin/bash trap 'increment' 2 increment() { echo "Caught SIGINT ..." X=`expr ${X} + 500` if [ "${X}" -gt "2000" ] then echo "Okay, I'll quit ..." exit 1 fi } ### main script X=0
while : do echo "X=$X" X=`expr ${X} + 1` sleep 1
done What does this script do? _______________________________________________ How can one hasten the exit of this script? __________________________________
trap 'echo "Control-Z disabled."' SIGTSTP while true do clear echo "Server Name - $(hostname)" echo "-------------------------------" echo " M A I N - M E N U" echo "-------------------------------" echo "1. Display date and time." echo "2. Display what users are doing." echo "3. Display network connections." echo "4. Exit" read -p "Enter your choice [ 1 -4 ] " choice case $choice in 1) echo "Today is $(date)" read -p "Press [Enter] key to continue..." readEnterKey ;; 2) w read -p "Press [Enter] key to continue..." readEnterKey ;; 3)
read -p "Press [Enter] key to continue..." readEnterKey ;; 4) echo "Bye!" exit 0
;; *) echo "Error: Invalid option..." read -p "Press [Enter] key to continue..." readEnterKey ;; esac done Try to interrupt the script in action by using ctrl-c and ctrl-z signals. Describe the result Ctrl-c __________________________ Ctrl-z __________________________ Create the following script in your bin directory as lab5c.sh #!/bin/bash times=0
n=0 warning(){ echo -e "\n*** CTRL+C and CTRL+Z keys are disabled. Please enter number only. Enter integer then hit [Enter] key to continue..." } trap 'warning' SIGINT SIGQUIT SIGTSTP while true do read -p "Enter number (-9999 to exit) : " n [ $n -eq -9999 ] && { echo "Bye!"; break; } [ $n -eq 0 ] && continue # % is the modulus operatore it returns the remainder of integer division ans=$(( n % 2 )) [ $ans -eq 0 ] && echo "$n is an even number." || echo "$n is an odd number." times=$(( ++times )) done trap - SIGINT SIGQUIT SIGTSTP echo "You played $times times." exit 0
Describe the operation of this script: ____________________________________________ Create the script as file lab5d.sh in your bin directory. This is another version of the recursive function factoral. #!/bin/bash factorial() { local i=$1 local f
[ $i -le 2 ] && echo $i || { f=$(( i - 1 )); f=`factorial $f`; f=$(( f * i )); echo $f; } } [ $# -eq 0 ] && { echo "Usage: $0 number"; exit 1; } result=`factorial $1` echo Factorial of $1 = $result Test the script on the following numbers: 15! = ____________________________ 75! = ___________________________ Create a script using the following function definition in your bin directory call it lab5e.sh is_file_dir(){ # $f is local variable local f="$1" # file attributes comparisons using test i.e. [ ... ] [ -f "$f" ] && { echo "$f is a regular file."; } [ -d "$f" ] && { echo "$f is a directory."; } [ -L "$f" ] && { echo "$f is a symbolic link."; } [ -x "$f" ] && { echo "$f is an executable file."; } }
Create a script using the following function definition in your bin directory, call it lab5f.sh. hello() { echo "Hello $1, let us be a friend." ; } add code to prompt for a person's name then pass it to the function and have the message appear on the screen. Спампаваць 30.1 Kb. Поделитесь с Вашими друзьями:
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