Experiment six: shell programming
Experimental Procedure
- log in system.
a. Using a user name and password to create a system test.
b. Open the Terminal application.
- Basics:
a. Understand the role shebang statement.
b. Grasp two ways to execute a shell script:
name of the shell script name
Executable script
c. For the following script, it was executed in two ways.
- Create a shell script service, complete the following functions:
a. Clear the screen.
b. Jump two lines.
c. Displays the current date and time.
d. Displays the current number of users.
e. Beep, and then displays the message "Now at your service".
answer:
clear
echo -e "\n\nDateTime:`date`"
echo -e "\nUser Number:`who | wc -l`"
echo -e "\07\nNow at you service"
- Create a shell script max, requirements are as follows:
a. User three numbers.
b. Obtain the maximum number of them and display.
answer:
if [ $1 -gt $2 ]
then
max=$1
else
max=$2
be
if [ $max -lt $3 ]
then
max=$3
be
echo "The max is: $max"
exit 0
- Create a shell script sum, requirements are as follows:
a. Use of: $ sum ab, where a and b represent two numbers, a <b.
b. Function from a to b is calculated and accumulated.
c. Displayed on the screen: a + ... + b = result. and the result is accumulated.
answer:
if [ $1 -ge $2 ]
then
exit 1
be
a=$1
b=$2
sum=0
while [ $a -le $b ]
do
sum=`expr $sum + $a`
a=`expr $a + 1`
done
echo "$1+…+$2=$sum"
exit
- Create a shell script check, requirements are as follows:
a. Whether there .profile file, output test results to check the current home directory.
b. If there is no .profile file, create a .profile file.
c. And add the following two lines of information at the end of .profile:
echo “Hello, Welcome to Linux!”
echo “Current Date and Time: [`date`]”
answer:
cd
if [ ! -e .profile ]
then
touch .profile
echo "Not exist .profile"
else
echo "Exist .profile"
be
echo 'echo "Hello, Welcome to Linux!"' >> .profile
echo 'echo "Current Date and Time:`date`"' >>.profile
echo "Write Success!"
exit 0
