Checking a variable

[abdelilah]

Hello

I've created (as a homework) to create as many folders as told but I still need to check if the variable is a number or not :

#!/bin/sh
echo "Veuillez saisir un nombre"; read nmbr
nmbrf=$nmbr
while [ $nmbrf -gt 0 ]
	do mkdir -p "foo$nmbrf"
	nmbrf=`expr $nmbrf - 1`
	echo "$nmbrf"
done

Question : how do I check that nmbr is a number or something else ? thanks in advance.

[Cabhan]

Homework questions are not allowed on these forums as per the rules:
http://www.linuxforums.org/forum/lin...ums-rules.html

As a bit of a hint: you can treat $nmbr as a string. If the string was also a valid number, what properties would it have?