AIX

lsdev -Cc processor
lsattr -El $proc -a type -F value

Perl Script

my $proc = (split(/\s/,(`lsdev -Cc processor`)[0]))[0];
my $type = `lsattr -El $proc -a type -F value`;
chomp $type;

Linux

cat /proc/cpuinfo | grep "model name"

Solaris

uname -p