Re: Can Bash do simple math?

[Greg Wooledge]

On Tue, Aug 06, 2024 at 15:11:26 +0200, Emanuele Torre wrote:
> On Tue, Aug 06, 2024 at 07:02:36AM -0400, Greg Wooledge wrote:
> > On Tue, Aug 06, 2024 at 11:35:43 +0200, bash@blaklinten.xyz wrote:
> > > My guess is that the $SECONDS variable was updated by Bash _after_ my
> > > assignment but _before_ the printf command, resulting in a "erroneous"
> > > value being printed. A kind of race condition, perhaps :)
> > 
> > It certainly sounds like one.  You might want to write a separate message
> > to the bug-bash@gnu.org mailing list about it.
> > 
> 
> No, that is docuemented:
> 
>    SECONDS
>      Each time this parameter is referenced, it expands to the number of
>      seconds since shell invocation. If a value is assigned to SECONDS,
>      the value returned upon subsequent references is the number of
>      seconds since the assignment plus the value assigned.  The number
>      of seconds at shell invocation and the current time are always
>      determined by querying the system clock. If SECONDS is unset, it
>      loses its special properties, even if it is subsequently reset.
> 
> I've used it a bunch of times to time stuff.

Ahhh, sorry, I forgot you have to explicitly *unset* it to turn off the
special behavior.  I was thinking that just assigning a value to it would
do that.