bash script - is a argument a string or a number?

[ph34r]

One of the guys I work with wants to write a bash script that will accept a argument or two. *I know to access the args as $1, $2, $N - but how can I check if that argument is a number or a string? I know bash variables are untyped, but if $1 contains a number I want to do one thing if it is a string I want to do another.

[cloverm]

I know nothing about bash scripting, but can you use Regular Expressions in bash?

[Feztaa]

You could use egrep to get your regular expressions:

if $(echo $1 | egrep '[0-9]'); then

(untested, but should work).

[pam]

You could use egrep to get your regular expressions:

if $(echo $1 | egrep '[0-9]'); then

(untested, but should work).

heh, famous last words, those
That would pass anything that had a mixture of numbers and other stuff. You could change it to

if $(echo $1 | egrep '^[0-9]*$'); then

also untested - it might work. :P

[Feztaa]

Oops, yeah heh

Actually, since you used *, that'll match an empty string, too. You should make it '^[0-9]+$', so that it only matches if there is at least one number. Untested, but it ought to work

[ph34r]

if (echo $1 | egrep '[0-9]' > /dev/null)
then
 *echo number
else
 *echo NaN
fi

This works... *Thanks to all for the help.