What are the ways to get ram size in Linux operating system?

Here is some methods to find ram size in Linux operating systems like Ubuntu, Debian, Fedora, CentOS, Red Hat.

Getting Ram Size With meminfo

Proc file system provides coonfiguration information about the current opoerating system. We can get information from direcly kernel provided /proc/meminfo . We can see a lot of information parameter with meminfo

$cat /proc/meminfo      
MemTotal:        1016756 kB 
MemFree:          159240 kB 
MemAvailable:     417356 kB 
Buffers:             868 kB 
Cached:           362436 kB 
SwapCached:            0 kB 
Active:           433572 kB 
Inactive:         306476 kB 
Active(anon):     377436 kB 
Inactive(anon):     7756 kB 
Active(file):      56136 kB 
Inactive(file):   298720 kB 
Unevictable:           0 kB 
Mlocked:               0 kB 
SwapTotal:             0 kB 
SwapFree:              0 kB 
Dirty:                 0 kB 
Writeback:             0 kB 
AnonPages:        376776 kB 
Mapped:           101996 kB 
Shmem:              8448 kB 
Slab:              53196 kB 
SReclaimable:      31768 kB 
SUnreclaim:        21428 kB 
KernelStack:        5104 kB 
PageTables:        22476 kB 
NFS_Unstable:          0 kB 
Bounce:                0 kB 
WritebackTmp:          0 kB 
CommitLimit:      508376 kB 
Committed_AS:    2269324 kB 
VmallocTotal:   34359738367 kB 
VmallocUsed:      143472 kB 
VmallocChunk:   34359591920 kB 
HardwareCorrupted:     0 kB 
AnonHugePages:    145408 kB 
HugePages_Total:       0 
HugePages_Free:        0 
HugePages_Rsvd:        0 
HugePages_Surp:        0 
Hugepagesize:       2048 kB 
DirectMap4k:       59236 kB 
DirectMap2M:      989184 kB 
DirectMap1G:           0 kB

• As we see there is a lot of details. Actually a lot of monitoring applications gets data from here.
• MemTotal is total ram size

Get Ram Size With Simple free Command

We can get ram size with simple free command.

$free  
              total        used        free      shared  buff/cache   available 
Mem:        1016756      441008      159324        8448      416424      417416 
Swap:             0           0           0

But this will give information with kilobyte size. We want to get megabyte

$free -m 
              total        used        free      shared  buff/cache   available 
Mem:            992         430         155           8         406         407 
Swap:             0           0           0

Or I think gigabyte is better

$ free  -g 
              total        used        free      shared  buff/cache   available 
Mem:             15          11           0           1           3           2 
Swap:             0           0           0

Getting Ram Size With vmstat

Another tool is vmstat as you see below

$vmstat -s | grep "total memory"  
      1016756 K total memory

How To Get Ram Size In Linux? Infografic