Как правильно посмотреть используемую память (ОЗУ)

free: invalid option -- 'h'
usage: free [-b|-k|-m|-g] [-l] [-o] [-t] [-s delay] [-c count] [-V]
  -b,-k,-m,-g show output in bytes, KB, MB, or GB
  -l show detailed low and high memory statistics
  -o use old format (no -/+buffers/cache line)
  -t display total for RAM + swap
  -s update every [delay] seconds
  -c update [count] times
  -V display version information and exit

Usage:
 free [options]

Options:
 -b, --bytes         show output in bytes
 -k, --kilo          show output in kilobytes
 -m, --mega          show output in megabytes
 -g, --giga          show output in gigabytes
     --tera          show output in terabytes
 -h, --human         show human readable output
     --si            use powers of 1000 not 1024
 -l, --lohi          show detailed low and high memory statistics
 -o, --old           use old format (no -/+buffers/cache line)
 -t, --total         show total for RAM + swap
 -s N, --seconds N   repeat printing every N seconds
 -c N, --count N     repeat printing N times

      --help    display this help text
 -V, --version  output version information and exit

For more details see free(1).

[mishapk@pc ~]$ free -h
             total       used       free     shared    buffers     cached
Mem:          734M       605M       128M       5,6M        39M       244M
-/+ buffers/cache:       322M       412M
Swap:           0B         0B         0B

a1ba@gentoohome ~ $ free -h
             total       used       free     shared    buffers     cached
Mem:          3,0G       2,8G       184M        26M        19M       845M
-/+ buffers/cache:       1,9G       1,0G
Swap:           0B         0B         0B

ross@coffin /home/ross pts/2> /root/bin/free
SYSTEM MEMORY INFORMATION:
mem_wire:        2378465280 (   2268MB) [ 28%] Wired: disabled for paging out
mem_active:  +   2580283392 (   2460MB) [ 31%] Active: recently referenced
mem_inactive:+   3021099008 (   2881MB) [ 36%] Inactive: recently not referenced
mem_cache:   +     69853184 (     66MB) [  0%] Cached: almost avail. for allocation
mem_free:    +    225136640 (    214MB) [  2%] Free: fully available for allocation
mem_gap_vm:  +      3297280 (      3MB) [  0%] Memory gap: UNKNOWN
-------------- ------------ ----------- ------
mem_all:     =   8278134784 (   7894MB) [100%] Total real memory managed
mem_gap_sys: +    268271616 (    255MB)        Memory gap: Kernel?!
-------------- ------------ -----------
mem_phys:    =   8546406400 (   8150MB)        Total real memory available
mem_gap_hw:  +     43528192 (     41MB)        Memory gap: Segment Mappings?!
-------------- ------------ -----------
mem_hw:      =   8589934592 (   8192MB)        Total real memory installed

SYSTEM MEMORY SUMMARY:
mem_used:        5273845760 (   5029MB) [ 61%] Logically used memory
mem_avail:   +   3316088832 (   3162MB) [ 38%] Logically available memory
-------------- ------------ ----------- ------
mem_total:   =   8589934592 (   8192MB) [100%] Logically total memory

MemTotal:        1554360 kB
MemFree:          802368 kB
Buffers:           29240 kB
Cached:           371312 kB
SwapCached:            0 kB
Active:           410956 kB
Inactive:         291500 kB
Active(anon):     302148 kB
Inactive(anon):     9624 kB
Active(file):     108808 kB
Inactive(file):   281876 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:        661448 kB
HighFree:           8588 kB
LowTotal:         892912 kB
LowFree:          793780 kB
SwapTotal:       3142652 kB
SwapFree:        3142652 kB
Dirty:               124 kB
Writeback:             0 kB
AnonPages:        301932 kB
Mapped:           111700 kB
Shmem:              9872 kB
Slab:              20472 kB
SReclaimable:      11624 kB
SUnreclaim:         8848 kB
KernelStack:        2136 kB
PageTables:         6380 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     3919832 kB
Committed_AS:    1329308 kB
VmallocTotal:     122880 kB
VmallocUsed:       11624 kB
VmallocChunk:     108784 kB
HardwareCorrupted:     0 kB
AnonHugePages:         0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       32760 kB
DirectMap2M:      878592 kB