UNIX for Dummies Questions & Answers

How can i do something, that will be doing periodicaly for 24 hours
and then do something else.
For example:

i want to write "time" in a text file every 10 sec
but only for the next 24 h and then rewrite all that data to an other file,
then again write "time" in the first file every 10 sec, but it must not contain
any of the old "time" just the new data and repeat that over and over...

while true; do

sleep 10
echo -e " +%T" >> present.txt

after 24 h do...
present.txt >> old.txt and delete all data in the present.txt, so it
can store new data

Code:

#!/bin/sh

time=0;

while true; do

until [ $time = 86400 ]; do
date "+%T" >> present.txt
time=$(($time+10))
sleep 10
done

time=0
cp present.txt present.old
>present.txt
done

pseudocoder's answer is correct conceptually and basically a good idea. However unix does not play fair. sleep 10 guarantees a minimum of 10 seconds, it could and sometimes is more.

At the end of the day you could have slipped by any number of seconds and therefore miss the intedned "until" limit in the code completely

Pete|1 - what are you trying to accomplish?

I'm trying to acomplish this https://www.unix.com/homework-coursew...-user-log.html

You are pushing the limits on the rules here.

There are two ways,one using C and the wptmp[x] file, the other with who
using what pseudocoder gave you

Code:

t=0
while [ t -le 86400 ]; do
  echo " `date +%T`  Users: `who | wc -l`"
  t=$((  $t + 1 ))
done > list.txt

The forums here are really NOT for homework; they are for unix users with problems.
We have a forum for homework. Posting homework outside the homework forum is not supposed to happen. Please do not do it again.

As you can see a partial answer is simple. You get to do some work to extend it to a 'forever solution'. Your prof wanted you to use 3 commands - date and who and wc.

Thanks for everything