Re: [Help-bash] Bug/limitation in 'time'

[Greg Wooledge]

On Mon, Mar 18, 2013 at 12:46:51AM -0700, Linda Walsh wrote:
> To do the above, you'd want to pre-init
> (I'd use i=${1:?"need start count"} in bash, but don't know if that is 
> portable)
> 
> so, assuming I know i is > 0:
> i=$1; while $((i-=1)); do :; done

The $((...)) expansion is not a command, so you can't use it after a
"while" or "if".  That's the role of ((...)) which, as already stated
several times in this thread, is *not* portable.

Personally, if I'm writing for POSIX sh, I'd do it this way:

i=$1
while [ $i -gt 0 ]; do
  i=$((i-1))
done

Of course that's assuming it makes sense to count downward in the script.
If you have to count upward for application reasons, then obviously do
it in reverse.