Ubuntu - Memory - Check Memory Usage

egrep "Mem|Cache|Swap" /proc/meminfo

returns:

MemTotal:       65980936 kB
MemFree:        23838680 kB
MemAvailable:   53968796 kB
Cached:         29046264 kB
SwapCached:            0 kB
SwapTotal:        999420 kB
SwapFree:         999420 kB