Convert string into integer in bash script - “Leading Zero” number error

Question

In a text file, test.txt, I have the next information:

sl-gs5 desconnected Wed Oct 10 08:00:01 EDT 2012 1001

I want to extract the hour of

Answer 1

what I'd call a hack, but given that you're only processing hour values, you can do

 hour=08
 echo $(( ${hour#0} +1 ))
 9
 hour=10 
 echo $(( ${hour#0} +1))
 11

with little risk.

IHTH.

Answer 2

You could also use bc

hour=8
result=$(echo "$hour + 1" | bc)
echo $result
9