1. Write a command that will:
a) shutdown the system in 25 minutes
b) halt the system immediately

2. Write a script called "shutdown" that accepts the initial OS shutdown value (seconds) as a command-line argument and after that shuts down the operating system. The scrip should prints output similar to the following:
>>user$ ./shutdown.sh 4
4
3
2
1
System will shut down immediately!

Thanks for your help!

Show us what you've done and where you're having problems and we'll offer assistance, but we don't answer homework questions verbatim.

cool see for your hint to this question.

and show us some effort.

1) For first 25min one:

-----------------------
#!/bin/bash

echo Shutting down in 25 minutes...
sleep 25m
shtudown -h now
----------------------

2) For immediately:

--------------------------
#!/bin/bash
echo Shutting down the system immediately...
shutdown -h now
--------------------------

3) For shutdown in seconds with countdown

------------------------------
#!/bin/bash

ARG1="$1"

echo Shutting down in $ARG1 seconds...
while [ $ARG1 -ne 0 ]; do
echo $ARG1
ARG1=$(($ARG1-1))
sleep 1s
done

echo "System will shut down immediately!"
shutdown -h now
-----------------------------

Just type in the text between the hypenated lines in a text files. And run

chmod u=rwx filename
and run

./filename
or in case of last script
./filename 4

and there you go.

Enjoy!!!

1 members found this post helpful.

It sounds like a homework assignment...

@OP well you found the cooked solution for this one:

for 1: try looking on "at" that 's quite clean and good for these sorts of tasks.. i would not prefer telling the shell to sleep for 25 mins
i am suggesting so you can do your assignments on your own next time..

Homework. ... A.....