Linux Commands - System statistic commands
Reference Linux
Following are some of the important system statistic commands in Linux.
free -h
This command displays the amount of free and used memory in the system.
In the following example we are getting the free and used memory.
$ free -h
total used free shared buff/cache available
Mem: 1.9G 933M 208M 10M 851M 880M
Swap: 1.4G 780K 1.4G
df -h
This command reports the file system disk space usage.
In the following example we are getting the disk space usage.
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 969M 0 969M 0% /dev
tmpfs 200M 1.5M 198M 1% /run
/dev/sda1 30G 6.0G 22G 22% /
...
...
...
iostat
This command reports the CPU (Central Processing Unit) statistics and I/O (input/output) statistics for devices and partitions.
In the following example we are getting the IO stats.
$ iostat
Linux 4.15.0-20-generic (yusufshakeel-ubuntu) Monday 01 January 2018 _x86_64_ (1 CPU)
avg-cpu: %user %nice %system %iowait %steal %idle
3.32 0.59 0.94 0.17 0.00 94.98
Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn
loop0 0.02 0.42 0.00 1048 0
loop1 3.68 4.09 0.00 10150 0
loop2 0.02 0.14 0.00 348 0
loop3 0.02 0.05 0.00 116 0
loop4 0.02 0.14 0.00 347 0
loop5 0.04 0.45 0.00 1114 0
loop6 0.02 0.05 0.00 120 0
loop7 0.02 0.14 0.00 350 0
scd0 0.02 0.07 0.00 186 0
sda 12.28 313.30 134.68 778389 334612
loop8 0.02 0.04 0.00 110 0
loop9 0.02 0.14 0.00 350 0
loop10 0.03 0.44 0.00 1082 0
loop11 3.03 3.15 0.00 7824 0
loop12 0.16 0.27 0.00 678 0
loop13 0.04 0.07 0.00 171 0
loop14 0.02 0.05 0.00 115 0
loop15 0.00 0.00 0.00 1 0
iostat -d 2
This will display a continuous device report at an interval of 2 seconds.
$ iostat -d 2
To break out of the continuous report press Ctrl+C.
vmstat
This command will report the virtual memory statistics.
In the following example we are getting the virtual memory stats.
$ 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 0 780 138884 85884 801708 0 0 245 103 89 374 3 1 96 0 0
mpstat
This command will display the process related statistics.
In the following example we are printing the processor related stats.
$ mpstat
Linux 4.15.0-20-generic (yusufshakeel-ubuntu) Monday 01 January 2018 _x86_64_ (1 CPU)
08:17:48 IST CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
08:17:48 IST all 2.96 0.41 0.72 0.12 0.00 0.03 0.00 0.00 0.00 95.75
tail -n N /var/log/syslog
This command will print the last N lines of the system log file.
In the following example we are printing the last 5 lines of the system log file.
$ tail -n 5 /var/log/syslog
Jan 9 08:22:26 yusufshakeel-ubuntu systemd[1]: Started Network Manager Script Dispatcher Service.
Jan 9 08:22:26 yusufshakeel-ubuntu nm-dispatcher: req:1 'connectivity-change': new request (1 scripts)
Jan 9 08:22:26 yusufshakeel-ubuntu nm-dispatcher: req:1 'connectivity-change': start running ordered scripts...
Jan 9 08:22:27 yusufshakeel-ubuntu whoopsie[662]: [08:22:27] online
Jan 9 08:45:02 yusufshakeel-ubuntu CRON[4228]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
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