Help with the 'LAST' command!

jaymdouglas · 04-05-2002, 10:38 AM

Allo,

I am hoping that someone could shed some light on my little problem that I have encountered.

I am trying to write a script that when run with no operands lists all the logged in user's online activity for the current month, then at the end of the list show the user's total time for that month.

So far I've got it pulling the LOGNAME and displaying that users times and dates, but I am having trouble in having them calculate the totals.

Here is what I have so far:

echo $LOGNAME > logfile
last | grep `cut –c1-8 logfile` > logfile
awk ‘{print $10}’ logfile > userlogs

cat userlogs

Here are the results:
in
(00:48)
(00:43)
(00:27)

If anyone knows how I can add these together then please shed some light on this subject.

Jay:smash:

acid_kewpie · 04-05-2002, 10:49 AM

is this homework? I've spent the last 30 mins working out your script really nicely, and i can tell you it works perfectly, but i get the impresion this is for an assignment, so i'm not going to show you unless you can guarentee it's not.

we're not here to do your education for you.

i've had 201 hours 54 minutes logged in on the last 4 days btw...

jaymdouglas · 04-05-2002, 11:28 AM

Homework…? I can only wish it was something like that...

No, this something that someone asked me to do at work. I'm actually the Visual Basic programmer / ASP guy here, and of course they assumed that I could do it.

My LINUX knowledge is extremely limited.

Your help would be appreciated.

Sorry about the double posting too.

Jay

acid_kewpie · 04-05-2002, 11:33 AM

hmm.. ok then, i checked your site and you say you're at college and all that...

ok, try this:

Code:

for i in `last | grep $LOGNAME | cut -d \( -f 2 | cut -c 1-5 | grep :`
do
  HOUR=`echo $i | cut -d ":" -f 1`
  MIN=`echo $i | cut -d ":" -f 2 `
  if [ $MIN -lt 10 ] 
  then
    MIN=`echo $MIN | cut -c 2`
  fi
  if [ $HOUR -lt 10 ]
   then
    HOUR=`echo $HOUR | cut -c 2`
  fi
  TOTALMIN=$(($TOTALMIN+$MIN))
  TOTALHOUR=$(($TOTALHOUR + $HOUR))
  if [ $TOTALMIN -gt 60 ]
  then
    TOTALMIN=$((TOTALMIN - 60))
    TOTALHOUR=$((TOTALHOUR + 1))
  fi
  echo `echo $i | cut -d ":" -f 1`:`echo $i | cut -d ":" -f 2`
done
echo ------
echo $TOTALHOUR:$TOTALMIN

You were using intermittent files in your attempts, not really a good idea.

and if anyone can tell me why on earth bash chokes when trying to evaluate $((31+ 08)) (i.e. the '0') that'd be nice... i wrote in those two inner 'if's to remove any leading 0's, which sucks

jaymdouglas · 04-05-2002, 06:02 PM

Thank you very much for your insight and your code.

It's working exactly as I hoped.

Jay

acid_kewpie · 04-05-2002, 06:08 PM

rah rah rah. I rock!

acid_kewpie · 04-05-2002, 06:09 PM

rah rah rah. I rock!

heh, i'm quite proud of that actaully... pretty basic, but it looks kinda impressive... maybe

Malicious · 04-06-2002, 09:33 AM

Quote:

Originally posted by acid_kewpie

and if anyone can tell me why on earth bash chokes when trying to evaluate $((31+ 08)) (i.e. the '0') that'd be nice... i wrote in those two inner 'if's to remove any leading 0's, which sucks

Most scripting languages interpret leading zeros on numeric items as octal as opposed to decimal. The 8 in 08 is not a valid octal (0-7) number.

echo $((31+08)); - should give error "value too great for base"

echo $((31+10#08)); - works fine.

Just prepend the "10#" (base 10) to all numbers if you expect leading zeros, at least for bash scripts. Other languages may vary.

At least one of these two should work.

HOUR="10#"`echo $i | cut -d ":" -f 1`
MIN=`echo "10#"$i | cut -d ":" -f 2 `

jaymdouglas · 04-06-2002, 09:29 PM

Now that you guys have gotten me officially hooked on LINUX programming, I wanted to take this script to the next level.

This script displays the total online time for the month that you’re on, how could you modify this code so you could select a particular month. e.g. ‘mylast Mar’ (from what I've read anyway)and then have it display the total online time for that month.

Thanks,

Jay