This isnt perl but I once had to do this with directory names in shell script

mkdir `awk -vmax=31 'BEGIN{for (i=1;i<=max;i++) printf "%.2d ",i; prin
+t}'`
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is one of the cooler ways ive found to do this, then there is seq

mkdir `seq -w 1 31`
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as I said not perl and a bit off the beaten track...