GNU/Linux Bash Command Tutorial for Beginners -3 System Statistic Commands

Hi,

I will continue to explain Linux Commands for Beginners in this tutorial series.

 

You should read second article before this.

 

 

3. System Statistic Commands

System statistic commands in Linux are generally used to learn about cpu, disk and memory, or other necessary information like hostname time TOP resource consumers about the system.

These commands are as follows.

  • df
  • du
  • free
  • hostname
  • time
  • who
  • lsmod
  • Vmstat
  • iostat
  • Top

 


df 

This command provides the user detailed information about disk usage.

Use and output of this command are as follows. df command shows disk usage in Bytes .

Df -k shows disk usage in Kilobytes and df -h shows in Gigabytes.

 

[root@MehmetSalih ~]# df
Filesystem           1K-blocks     Used Available Use% Mounted on
/dev/mapper/vg_oracletest-lv_root
                      20228748 15107056   4071068  79% /
tmpfs                 20480000   142892  20337108   1% /dev/shm
/dev/sda1               487652   122091    335865  27% /boot
/dev/mapper/vg_oracletest-lv_home
                      10190136  5259268   4390196  55% /home
/dev/mapper/vg_oracletest-LVDbOra1
                     165008748 76505512  80098244  49% /oradata
/dev/sdb1             61792296    53640  58593132   1% /backup
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# df -k
Filesystem           1K-blocks     Used Available Use% Mounted on
/dev/mapper/vg_oracletest-lv_root
                      20228748 15107060   4071064  79% /
tmpfs                 20480000   142892  20337108   1% /dev/shm
/dev/sda1               487652   122091    335865  27% /boot
/dev/mapper/vg_oracletest-lv_home
                      10190136  5259268   4390196  55% /home
/dev/mapper/vg_oracletest-LVDbOra1
                     165008748 76505560  80098196  49% /oradata
/dev/sdb1             61792296    53640  58593132   1% /backup
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_oracletest-lv_root
                       20G   15G  3.9G  79% /
tmpfs                  20G  140M   20G   1% /dev/shm
/dev/sda1             477M  120M  328M  27% /boot
/dev/mapper/vg_oracletest-lv_home
                      9.8G  5.1G  4.2G  55% /home
/dev/mapper/vg_oracletest-LVDbOra1
                      158G   73G   77G  49% /oradata
/dev/sdb1              59G   53M   56G   1% /backup
[root@MehmetSalih ~]# 






du

This command provides and summarize disk usage of each FILE, recursively for directories. Usage and output are as follows.

 

[root@MehmetSalih backup]# du
24 ./.patch_storage/29585399_Apr_9_2019_19_12_47/original_patch/custom/scripts
28 ./.patch_storage/29585399_Apr_9_2019_19_12_47/original_patch/custom
28 ./.patch_storage/29585399_Apr_9_2019_19_12_47/original_patch/etc/config
32 ./.patch_storage/29585399_Apr_9_2019_19_12_47/original_patch/etc
88 ./.patch_storage/29585399_Apr_9_2019_19_12_47/original_patch
100 ./.patch_storage/29585399_Apr_9_2019_19_12_47
180 ./.patch_storage/29517242_Apr_17_2019_23_27_10/original_patch/etc/config
184 ./.patch_storage/29517242_Apr_17_2019_23_27_10/original_patch/etc
268 ./.patch_storage/29517242_Apr_17_2019_23_27_10/original_patch
276 ./.patch_storage/29517242_Apr_17_2019_23_27_10
8 ./.patch_storage/NApply/2019-04-18_07-21-20AM
8 ./.patch_storage/NApply/2019-04-18_07-21-09AM
8 ./.patch_storage/NApply/2019-04-18_07-21-25AM
8 ./.patch_storage/NApply/2019-04-18_07-21-05AM
36 ./.patch_storage/NApply
436 ./.patch_storage
12 ./.opatchauto_storage/system_patches/29547676
20 ./.opatchauto_storage/system_patches
24 ./.opatchauto_storage
4 ./rman
468 .
[root@MehmetSalih backup]#


You can use du -sh command for disk usage in Gigabyte under spesific directory.

[root@MehmetSalih oradata]# 
[root@MehmetSalih oradata]# du -sh *
16G 13c
1.6G agent
20G app
9.4G app19c
177M arc_eksik.rman
2.3G em12105_linux64_disk1.zip
995M em12105_linux64_disk2.zip
1.3G em12105_linux64_disk3.zip
4.0K export
3.8G gc_inst
16K lost+found
17G middleware
4.0K oldbackup
1.6G oradata
119M OraInstall2017-04-21_03-24-54PM
1.2G swlib
26M thread_1_seq_4739.1080.926947103
[root@MehmetSalih oradata]#


free

This command provides the user with the amount of free and used memory(RAM) in the operating system. Its use is as follows.

 

[root@MehmetSalih ~]# free
             total       used       free     shared    buffers     cached
Mem:      49463392   49270332     193060   45031644     256076   45826880
-/+ buffers/cache:    3187376   46276016 
Swap:      4194300    3166452    1027848 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# free -k
             total       used       free     shared    buffers     cached
Mem:      49463392   49270368     193024   45031644     256092   45826896
-/+ buffers/cache:    3187380   46276012 
Swap:      4194300    3166452    1027848 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# free -m
             total       used       free     shared    buffers     cached
Mem:         48304      48115        188      43976        250      44752
-/+ buffers/cache:       3112      45191 
Swap:         4095       3092       1003 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# free -g
             total       used       free     shared    buffers     cached
Mem:            47         46          0         42          0         43
-/+ buffers/cache:          3         44 
Swap:            3          3          0 
[root@MehmetSalih ~]#

 

 

 

hostname

it displays the name of the machine. Use of this command is as follows.

 

[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# hostname
MehmetSalih
[root@MehmetSalih ~]# 

time

This command shows how long a given command is run. Its use is as follows.

[root@MehmetSalih ~]# time

real 0m0.000s
user 0m0.000s
sys 0m0.000s
[root@MehmetSalih ~]#

 

 

who

This command lists the active users in the system. Use of the command is as follows.

 

[root@MehmetSalih ~]# who
root pts/0 2019-09-09 13:52 (ittutorial.org)
root pts/1 2019-09-09 13:56 (ittutorial.org)
oracle pts/2 2019-09-16 17:13 (:2.0)
root pts/3 2019-09-10 11:44 (ittutorial.org)
oracle pts/4 2019-09-16 16:46 (:2.0)
[root@MehmetSalih ~]#


lsmod

This command provides the user with information about all modules installed in the operating system. Use of the command is as follows.

 

 

[root@MehmetSalih ~]# lsmod
Module Size Used by
fuse 77921 0 
oracleasm 53591 1 
autofs4 34292 3 
8021q 20994 0 
garp 7297 1 8021q
stp 2256 1 garp
llc 5608 2 garp,stp
ip6t_REJECT 4486 2 
nf_conntrack_ipv6 10595 3 
nf_defrag_ipv6 11368 1 nf_conntrack_ipv6
xt_state 1370 3 
nf_conntrack 84658 2 nf_conntrack_ipv6,xt_state
ip6table_filter 1671 1 
ip6_tables 18368 1 ip6table_filter
ipv6 339234 130 ip6t_REJECT,nf_conntrack_ipv6,nf_defrag_ipv6
ext3 214449 1 
jbd 73252 1 ext3
uinput 8917 0 
sg 30968 0 
vmw_balloon 6875 0 
serio_raw 5631 0 
vmxnet3 44918 0 
crc32c_intel 14496 0 
ghash_clmulni_intel 4707 0 
microcode 115607 0 
pcspkr 2150 0 
vmw_vmci 63353 0 
i2c_piix4 11994 0 
shpchp 27901 0 
ext4 533275 4 
jbd2 100929 1 ext4
mbcache 7575 2 ext3,ext4
sd_mod 41045 8 
crc_t10dif 1547 1 sd_mod
mptsas 59857 5 
mptscsih 45921 1 mptsas
mptbase 99360 2 mptsas,mptscsih
scsi_transport_sas 34071 1 mptsas
sr_mod 15980 0 
cdrom 40900 1 sr_mod
aesni_intel 45744 0 
ablk_helper 2997 1 aesni_intel
cryptd 10460 3 ghash_clmulni_intel,aesni_intel,ablk_helper
lrw 4222 1 aesni_intel
aes_x86_64 7967 1 aesni_intel
xts 3466 1 aesni_intel
gf128mul 7999 2 lrw,xts
pata_acpi 3782 0 
ata_generic 3758 0 
ata_piix 26525 0 
vmwgfx 128627 0 
ttm 80627 1 vmwgfx
drm 274140 2 vmwgfx,ttm
i2c_core 31228 2 i2c_piix4,drm
dm_mirror 14208 0 
dm_region_hash 11094 1 dm_mirror
dm_log 9681 2 dm_mirror,dm_region_hash
dm_mod 84383 14 dm_mirror,dm_log
[root@MehmetSalih ~]#







Vmstat

vmstat command displays information about processes, memory, paging, block IO and CPU activity.

If you use vmstat n, vmstat generates instant result in every n second.

 

[root@MehmetSalih ~]# 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 3166260 175388 264560 45839080    0    1    93    58    1    3  0  0 99  0  0
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]# vmstat 3
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 3166260 174564 264708 45839328    0    1    93    58    1    3  0  0 99  0  0
 0  0 3166260 174412 264976 45839348    0    0   626   188 6499 11970  0  0 99  0  0
 0  0 3166260 173284 264976 45839384    0    0   271    44 6289 11801  0  0 99  0  0
^C
[root@MehmetSalih ~]# 
[root@MehmetSalih ~]#

 

 

iostat

iostat displays CPU statistics and I/O statistics for devices, partitions and network filesystems (NFS).


[root@MehmetSalih ~]# iostat
Linux 3.8.13-118.13.3.el6uek.x86_64 (MehmetSalih)     09/16/2019      _x86_64_        (16 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.35    0.00    0.16    0.38    0.00   99.11

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda               8.63       107.10       141.16   66372171   87483024
sdd               0.00         0.00         0.00       2393          0
sdb               0.29        32.79        41.16   20324106   25505496
sdc              80.38      2825.08      1661.52 1750816266 1029715953
dm-0              1.26        43.82        28.99   27154355   17965160
dm-1              3.73        10.50        19.38    6507625   12009696
dm-2              0.01         0.03         0.04      16499      23944
dm-3             10.81        52.74        92.75   32685947   57484080

[root@MehmetSalih ~]#

 

TOP

top command displays dynamic real-time view of a running system. It can display system summary information as well as a list of tasks currently being managed by the Linux kernel.


[root@MehmetSalih ~]# top

top - 17:50:14 up 7 days,  4:09,  5 users,  load average: 0.28, 0.21, 0.19
Tasks: 503 total,   1 running, 502 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.3%us,  0.2%sy,  0.0%ni, 99.1%id,  0.4%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  49463392k total, 49289872k used,   173520k free,   265704k buffers
Swap:  4194300k total,  3166256k used,  1028044k free, 45839860k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                
13063 oracle    -2   0 1405m 1192 1048 S  1.7  0.0  70:43.21 asm_vktm_+asm                                                          
19390 root      20   0 15348 1444  824 R  1.7  0.0   0:00.08 top                                                                    
29901 oracle    -2   0 6580m  19m  17m S  1.7  0.0  66:29.81 ora_vktm_prod                                                          
    1 root      20   0 19412  576  352 S  0.0  0.0   1:39.06 init                                                                   
    2 root      20   0     0    0    0 S  0.0  0.0   0:00.56 kthreadd                                                               
    3 root      20   0     0    0    0 S  0.0  0.0   0:20.30 ksoftirqd/0                                                            
    5 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/0:0H                                                           
    6 root      20   0     0    0    0 S  0.0  0.0   0:05.90 kworker/u:0                                                            
    7 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/u:0H                                                           
    8 root      RT   0     0    0    0 S  0.0  0.0   0:00.01 migration/0                                                            
    9 root      20   0     0    0    0 S  0.0  0.0   0:00.00 rcu_bh                                                                 
   10 root      20   0     0    0    0 S  0.0  0.0   5:22.63 rcu_sched                                                              
   11 root      RT   0     0    0    0 S  0.0  0.0   0:00.93 watchdog/0                                                             
   12 root      RT   0     0    0    0 S  0.0  0.0   0:00.89 watchdog/1                                                             
   13 root      20   0     0    0    0 S  0.0  0.0   0:19.36 ksoftirqd/1                                                            
   14 root      RT   0     0    0    0 S  0.0  0.0   0:02.09 migration/1                                                            
   16 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/1:0H                                                           
   17 root      RT   0     0    0    0 S  0.0  0.0   0:00.95 watchdog/2                                                             
   18 root      20   0     0    0    0 S  0.0  0.0   0:18.61 ksoftirqd/2                                                            
   19 root      RT   0     0    0    0 S  0.0  0.0   0:00.04 migration/2                                                            
   21 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/2:0H                                                           
   22 root      RT   0     0    0    0 S  0.0  0.0   0:01.25 watchdog/3                                                             
   23 root      20   0     0    0    0 S  0.0  0.0   0:04.11 ksoftirqd/3                                                            
   24 root      RT   0     0    0    0 S  0.0  0.0   0:00.02 migration/3                                                            
   26 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/3:0H                                                           
   27 root      RT   0     0    0    0 S  0.0  0.0   0:01.26 watchdog/4                                                             
   28 root      20   0     0    0    0 S  0.0  0.0   0:01.58 ksoftirqd/4                                                            
   29 root      RT   0     0    0    0 S  0.0  0.0   0:00.02 migration/4                                                            
   31 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/4:0H                                                           
   32 root      RT   0     0    0    0 S  0.0  0.0   0:01.27 watchdog/5                                                             
   33 root      20   0     0    0    0 S  0.0  0.0   0:00.67 ksoftirqd/5                                                            
   34 root      RT   0     0    0    0 S  0.0  0.0   0:06.90 migration/5                                                            
   36 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/5:0H                                                           
   37 root      RT   0     0    0    0 S  0.0  0.0   0:01.29 watchdog/6                                                             
   38 root      20   0     0    0    0 S  0.0  0.0   0:06.32 ksoftirqd/6                                                            
   39 root      RT   0     0    0    0 S  0.0  0.0   0:00.04 migration/6                                                            
   41 root       0 -20     0    0    0 S  0.0  0.0   0:00.00 kworker/6:0H                                                           
   42 root      RT   0     0    0    0 S  0.0  0.0   0:01.26 watchdog/7                                                             
[root@MehmetSalih ~]#



I will continue to explain Linux commands in the next article.

  

Do you want to learn Linux System Administration for Beginners, then read the following articles.

Mehmet Salih Deveci

I am Founder of IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience. I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource. I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks. I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients. If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress mehmetsalih.deveci@outlook.com. -                                                                                                                                                                                                                                                 - Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  mehmetsalih.deveci@outlook.com a mail atabilirsiniz.