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Determine whether a CPU has 64 bit capability or not

Terminal - Determine whether a CPU has 64 bit capability or not
if cat /proc/cpuinfo | grep " lm " &> /dev/null; then echo "Got 64bit" ; fi
2010-04-10 15:31:58
User: xeor
Functions: cat echo grep
Determine whether a CPU has 64 bit capability or not

Check if you have 64bit by looking for "lm" in cpuinfo. lm stands for "long mem". This can also be used without being root.


There are 3 alternatives - vote for the best!

Terminal - Alternatives
sudo dmidecode --type=processor | grep -i -A 1 charac

Know a better way?

If you can do better, submit your command here.

What others think

This is a bit cleaner and simpler:

grep -q " lm " /proc/cpuinfo && echo "Got 64bit"
Comment by eightmillion 262 weeks and 6 days ago

Just a nitpick: "lm" stands for long mode (not long mem), meaning that the processor registers are 64bit long in this mode.

By the way, /proc/cpuinfo works on Linux only, of course, so this is not portable (except that it also works on FreeBSD when the "Linuxulator" is enabled and linprocfs mounted on /compat/linux/proc).

On Solaris use this command to find out if 64bit is supported by the platform:

isainfo -bv

On FreeBSD, this command can be be used:

grep -w "LM" /var/run/dmesg.boot && echo "Got 64bit"
Comment by inof 262 weeks and 6 days ago

My two cents, for Red Hat flavours:


sample output:

Comment by KoRoVaMiLK 262 weeks and 5 days ago

Your point of view

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