Command Linux – Technology Geek

1-Check Memory :

[oracle@192 ~]$ free -m

             total       used       free     shared    buffers     cached
Mem:          1010        997         13          0         71        685
-/+ buffers/cache:        240        770
Swap:         2000          0       2000

[oracle@192 ~]$ 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 0 28820 72248 704336 0 0 117 49 1026 239 3 1 93 3 0

[oracle@192 ~]$ dmesg | grep RAM

BIOS-provided physical RAM map:
hdc: ATAPI 1X DVD-ROM DVD-R-RAM CD-R/RW drive, 32kB Cache, UDMA(33)

Finally : top command that you could use.

2-How Much this Os was running

[oracle@192 ~]$ uptime

23:03:17 up 1:44, 2 users, load average: 0.04, 0.11, 0.08

3-Check Some Hardware Information

CPU :

[oracle@192 ~]$ cat /proc/cpuinfo

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 37
model name      : Intel(R) Core(TM) i5 CPU       M 430 @ 2.27GHz
stepping        : 2
cpu MHz         : 2261.079
cache size      : 3072 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 11
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss nx rdtscp lm constant_tsc up ida nonstop_tsc pni cx16 popcnt lahf_lm [8]
bogomips        : 4522.15

Thank you
Osama mustafa

Sometime you as DBA you need to check your memory On Operating System Level, i will give you some command will useful to you :

1-free -m / free -g

m : megabytes
g : gigabytes

              total    used     free   shared  buffers   cached 
 Mem:           503     451       52        0       14      293 
 -/+ buffers/cache:     143      360 
 Swap:         1027       0     1027

another example :

free -t -m

       total       used       free     shared    buffers     cached
Mem:           750        625        125          0         35        335
-/+ buffers/cache:        253        496
Swap:          956          0        956
Total:        1707        625       1082

2-vmstat

procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
1  0      0 131620  35432 341496    0    0    42    82  737  1364 15  3 81  1

3-top

4-gnome-system-monitor

The below Command for clear cache memory in linux

sync;

echo 3 > /proc/sys/vm/drop_caches

 you can make it as job in linux save in it crontab

0 * * * * /root/clearcache.sh

Create a file in '/root' called 'clearcache.sh' with the following content:

#!/bin/sh  
 sync; echo 3 > /proc/sys/vm/drop_caches

Thank you

osama mustafa

Tag: Command Linux

Another Linux Command

Check memory On Linux