bash increment in a given way

[Genes MailLists]

On 12/11/2010 09:34 AM, S Mathias wrote:

> but what's the "magic" for this? :
> 
> $ MAGIC; do echo "Welcome $i times"; done
> Welcome 0 times
> Welcome 1 times
> Welcome 4 times
> Welcome 5 times
> Welcome 8 times
> Welcome 9 times
> $
> 
> thanks:\
> 
> 

  Probably lots of ways to do this here's one:


 WeirdIncr () {
   typeset -i j
   typeset -i z
   j=$1
   z=$(expr $j % 2)
   if (( z == 0 )) ; then
     j="j+1"
   else
     j="j+3"
   fi
   echo $j
}

typeset -i i
let i=0
while (( i < 10 ))
do
   echo "Hi $i"
   i=$(WeirdIncr $i)
done