If I am working on a Unix machine, how could I know the size of the machine whether it is 64-bit or 32-bit machine?
AIX you can do this:
getconf KERNEL_BITMODE
HP-UX you can do this:
getconf KERNEL_BITS
or just:
getconf -a | grep KERN
Sun Solaris you can do this:
isainfo -v
For Linux, yes, the uname -a should do the trick
uname -a