Back in this post I said ‘there’s more than one way to do it’ should be a motto of Linux©.  We’re going to do it again, this time with memory.  There’s another way to do it.

There’s the free command that shows you how much you have:

Alpha:~ computerlamp$ free
             total       used       free     shared    buffers     cached
Mem:        509688     491316      18372          0      97264     208964
-/+ buffers/cache:     185088     324600
Swap:       262140        316     261824

And we can give it a flag to show that information in gigabytes:

Alpha:~ computerlamp$ free -g
             total       used       free     shared    buffers     cached
Mem:             0          0          0          0          0          0
-/+ buffers/cache:          0          0
Swap:            0          0          0

Wait, something’s wrong.  There’s no memory on this system?  Well, it turns out that this one is an older Alpha.  (I logged into the wrong system this morning) and it doesn’t even have a gigabyte of memory.  I have to give it the -m flag.

Alpha:~ computerlamp$ free -m
             total       used       free     shared    buffers     cached
Mem:           497        479         18          0         94        204
-/+ buffers/cache:        180        317
Swap:          255          0        255

I really should have logged into the new Alpha and not the old one.

Anyway, back to the old Alpha.  There’s another way to look at memory, this time we use the command vmstat.

Alpha:~ computerlamp$ vmstat
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0    316  18488  97276 209068    0    0     0     0    1    1  0  0 100  0  0

The columns under the memory tag show us how much we have sitting around.

So, there’s another way.  Always another way in Linux©.