C:\tmp>perl -e "open ++$fh, '>', $fh or die qq'$fh $!\n' for 1..$ARGV[0]" 512
510

[root@devel3 tmp]# perl -e 'open ++$fh, ">", $fh or die "$fh $!\n" for  1..$ARGV[0]' 1024
1022 Too many open files

##</code><code>##

[root@devel3 tmp]# ulimit -n 65535
[root@devel3 tmp]# perl -e 'open ++$fh, ">", $fh or die "$fh $!\n" for  1..$ARGV[0]' 2048
[root@devel3 tmp]# ls 204?
2040  2041  2042  2043  2044  2045  2046  2047  2048
[root@devel3 tmp]#