C:\>perl -MScalar::Util=looks_like_number -e "print looks_like_number 'Inf'"
20

##</code><code>##

looks_like_number EXPR
Returns true if perl thinks EXPR is a number. See "looks_like_number" in perlapi.

##</code><code>##

C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number 'Inf'"
20
C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number 'foo'"
0
C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number 'inf'"
20
C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number '7'"
1
C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number '7874321907'"
2
C:\>perl -e "use Scalar::Util(looks_like_number); print looks_like_number(7874321907)"
8704