Find out it is a 32 or 64-bit Linux

Use the command
uname -m
If it shows x86_64, it is a 64-bit host.
If it shows i386 (or sometimes i686), it is a 32-bit machine

Plus, run the command
file /bin/ls
For 64-bit kernel, it should show
/bin/ls: ELF 64-bit LSB executable ....