Bash script: How do I check if $1 is an integer?

[Wallex]

$1 is supposed to go between 1 and 100, I can do the range check using the test function, but if I use a char or something non-numerical, it will bark back at me with a "[: a: integer expression expected" msg. I read the man for test and apparently there's no way to test if a var can be interpreted as a number. I've managed my own by doing a test which asks if the value is between 0 and 100 (otherwise includes nonnumerical values for $1) so, my script works. I just am annoyed that that error messages pops up... how can I 'catch' or hide that error message? Or how should I be asking 'in a safe way' that $1 is in the 0-100 range? Currently what I do is:
if [ $vol ]
then
if ! [ $vol -ge 0 ] || ! [ $vol -le 100 ]
then
echo $vol is an invalid value. Range is [0-100]
return 1
fi
fi

[bwkaz]

Wow, that's odd. I would have figured it's easy enough to add to the "test" program, but apparently not.

Hmm... I'd be interested in finding out what to use for this as well.

[uptimenotifier]

Try something like this:

if [ $vol ]
then
if [ ! $(echo "$vol" | grep -E "^[0-9]+$") ]
then
echo $vol is not a valid integer.
exit 1
else
if ! [ $vol -ge 0 ] || ! [ $vol -le 100 ]
then
echo $vol is an invalid value. Range is [0-100]
exit 1
fi
fi
fi

[bwkaz]

Ah yes, duh, grep. I should have thought of that one! :p

[Wallex]

The wonders of grep... thanks for the info!