Because backticks don't nest.
If your shell supports the more modern $(...)
syntax, try this:
var1=$(expr $RANDOM % 100)
var2=$(expr $RANDOM % 1000 \* 60)
...
...
sleep $(expr $var2 - $(date -t) + $var1)
If not, you can store the intermediate value in another variable:
var1=`expr $RANDOM % 100`
var2=`expr $RANDOM % 1000 \* 60`
...
...
date=`date -t`
sleep `expr $var2 - $date + $var1`
(I've also added a space, changing $var2-
to $var2 -
.)
Incidentally, I was unable to try this, since on my system the date
command has no -t
option.