1. Write a script that prints the current date, your user name, and the name of
ID: 640930 • Letter: 1
Question
1. Write a script that prints the current date, your user name, and the name of your login shell. Use variables and/or commands. Do not use literals.
2. Write a script that creates three background processes, waits for them all to complete, and then displays a simple message.
3. Experiment with the exec command by writing a series of three shell scripts called "a.sh," "b.sh," and "c.sh" that each display their name using a command line parameter, execute ps, and then exec the next script in the sequence. Observe what happens when you start the first script by: exec a.sh (Note: You are going to link your files to my working directory, so make sure your naming of and/or pathing to the files will work when they run in my directory.)
4. Write a script that echos the following special variable: $$, $0, $1, ${10}, $*, $@, and $#. The script must work with the input and output below. Your pid will be different but the rest of the rest will match.
5. Write a script that clears the screen, determines how many sessions you are in (use who, grep, and wc), compare 2 files that are passed as parameters using diff and cmp, and sort the first file.
Explanation / Answer
Hope it may helps you...
Answer for 1 is:
# function to display a line of asterices
function line(){
echo "*************************************************"
}
echo "Your username : $(echo $USER)"
line # call function
echo "Current date and time : $(date)"
line
echo "Currently logged on users:"
who
Answer for 2 is:
#Grab the parameter off the command line delay=5
pid=$1
cmd=$2
usage=0;
if [ "$pid" == "" ] then
usage=1;
echo "PID is required"
fi
if [ "$cmd" == "" ] then
usage=1;
echo "COMMAND is required"
fi
if [ "$usage" == "1" ] then
echo "usage: waitforpid.sh PID COMMAND"
echo " where"
echo " PID = Process id to wait for"
echo " COMMAND = Command to be executed after it completes"
exit
fi
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