Linux Command Tool

w(who),nomn,ncdu,iftop,findmnt,htop,ccze,glances

For the original picture, please see the original Mipu blog: Linux Command Tool

1,w (who)

Yes, you're right. It's the w command. It's used in a similar way to who.

Using this command, we can see who the user is currently logged in to the system and what commands have been executed.

[root@mimvp-hz ~]# w
 06:28:20 up 239 days, 19:19,  2 users,  load average: 0.41, 0.43, 1.18
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/1    106.39.150.123   Thu07    0.00s  0.02s  0.00s w
root     pts/0    106.39.150.123   06:12    1:48   0.02s  0.02s -bash
[root@mimvp-hz ~]# who
root     pts/1        2018-08-09 07:57 (106.39.150.123)
root     pts/0        2018-08-12 06:12 (106.39.150.123)

2,nomn

nomn can view CPU, kernel status, memory, network, disk.

Before using this instruction, you need to install it with the yum install nmon-y instruction.

After installation, the instruction can be opened by executing nomn.

According to the help, input c to view CPU, input m to view memory, input n to view network, as follows

3,ncdu

Like nomn, this instruction needs to be installed first with the yum install ncdu-y instruction.

The ncdu command can be used to view and analyze the disk space occupied by directories in Linux.

After installation, the ncdu command is executed and analyzed by default from the current directory. Executing the command will take up a lot of disk I/O.

When the analysis is completed, output similar to the following screenshot is generated:

We can sort by name n in the result interface, or by size s.

4,iftop

Manual installation required: Yum install iftop-y

iftop is a real-time traffic monitoring tool, which monitors TCP/IP connections and so on. The disadvantage is that it has no report function and must run as root.

If we run the iftop command directly, we will monitor the real-time traffic of the first network card by default, which is usually combined as iftop-i eth1-n-P.

The scale range shown above the interface is similar to that of a scale, which is used as a ruler for long strips showing flow patterns. (Quit the interface directly by q)

The middle <==> arrows indicate the direction of traffic.

TX: Send traffic

RX: Received traffic

TOTAL: Total Flow

cum: Total traffic from running iftop to the current time

Peak: peak traffic

rates: Indicate the average traffic of the past 2s 10s 40s, respectively

5,findmnt

Findmnt is a Linux built-in command line tool that doesn't need to be installed. It's mainly used to find the status of mounted filesystems.

Findmnt can view the devices that have been mounted in the current system, and mount or unmount operations can be performed if necessary.

After executing the findmnt command, you will see the following input:

# findmnt
TARGET                       SOURCE                     FSTYPE      OPTIONS
/                            /dev/xvda1                 ext4        rw,relatime,barrier=1,data=ordered
├─/proc                      proc                       proc        rw,relatime
│ ├─/proc/bus/usb            /proc/bus/usb              usbfs       rw,relatime
│ ├─/proc/sys/fs/binfmt_misc                            binfmt_misc rw,relatime
│ ├─/proc/fs/nfsd            nfsd                       nfsd        rw,relatime
│ └─/proc/xen                                           xenfs       rw,relatime
├─/sys                       sysfs                      sysfs       rw,relatime
├─/dev                       devtmpfs                   devtmpfs    rw,relatime,size=951760k,nr_inodes=237940,mode=755
│ ├─/dev/pts                 devpts                     devpts      rw,relatime,gid=5,mode=620,ptmxmode=000
│ └─/dev/shm                 tmpfs                      tmpfs       rw,relatime
├─/home/data                 /dev/xvdb                  ext3        rw,relatime,errors=continue,barrier=1,data=ordered
├─/var/lib/nfs/rpc_pipefs    sunrpc                     rpc_pipefs  rw,relatime
└─/home/data2-bj             123.57.78.100:/home/data2/ nfs4        rw,relatime,vers=4,rsize=262144,wsize=262144,namlen=255,hard,

As you can see above, the root directory /, and / home/data, / home-data2-bj are all hard drives with data.

View the local hard disk through df-h

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1             40G   21G   18G  54% /
tmpfs                 938M     0  938M   0% /dev/shm
/dev/xvdb             9.9G  7.6G  1.9G  81% /home/data
123.57.78.100:/home/data2
                       20G  4.6G   15G  25% /home/data2-bj

Of course, the following parameters are available:

Findmnt-l: Output in tabular form

Findmnt-s: Output device mounted in fstab

Findmnt-t ext4: Output by file system type

# findmnt -t ext4
TARGET SOURCE     FSTYPE OPTIONS
/      /dev/xvda1 ext4   rw,relatime,barrier=1,data=ordered

6,htop

The function of this instruction is similar to that of top, except that the interface is more elaborate and has a beautiful load interface, which needs to be installed with Yum install htop-y before running.

After installation, enter the htop command

Here are some shortcut keyboard settings for htop interactive output:

M sorts processes according to memory usage

P sorts processes according to CPU usage

Access help information

k Closes the current/tagging process

F2 sets htop

You can choose the display option here. / Search process.

7,ccze

This command can be used to highlight logs in different colors to help users view and analyze. Before using this command, we need to install it with Yum install ccze-y.

Then you can use the tailf/var/log/cron | ccze command to view the log at the end of the static log

If you want to highlight the color to view the real-time log, execute tail-f/var/log/*_log | ccze

Obviously, after using the ccze command, the error prompt in the log is highlighted in red, which is very conspicuous.

Using the ccze-l parameter, you can see the log types it supports.

# ccze -l
Available plugins:
 
Name      | Type    | Description
------------------------------------------------------------
apm       | Partial | Coloriser for APM sub-logs.
distcc    | Full    | Coloriser for distcc(1) logs.
exim      | Full    | Coloriser for exim logs.
fetchmail | Partial | Coloriser for fetchmail(1) sub-logs.
ftpstats  | Full    | Coloriser for ftpstats (pure-ftpd) logs.
httpd     | Full    | Coloriser for generic HTTPD access and error logs.
icecast   | Full    | Coloriser for Icecast(8) logs.
oops      | Full    | Coloriser for oops proxy logs.
php       | Full    | Coloriser for PHP logs.
postfix   | Partial | Coloriser for postfix(1) sub-logs.
procmail  | Full    | Coloriser for procmail(1) logs.
proftpd   | Full    | Coloriser for proftpd access and auth logs.
squid     | Full    | Coloriser for squid access, store and cache logs.
sulog     | Full    | Coloriser for su(1) logs.
super     | Full    | Coloriser for super(1) logs.
syslog    | Full    | Generic syslog(8) log coloriser.
ulogd     | Partial | Coloriser for ulogd sub-logs.
vsftpd    | Full    | Coloriser for vsftpd(8) logs.
xferlog   | Full    | Generic xferlog coloriser.

8,glances

Glasnces is a reporting tool similar to nmon, which can report and count CPU, memory, network, disk, process.

Except for reporting statistics, Glance does not support any other features or functions.

Execute the installation: Yum install glances-y. Run the glances command directly to view the statistics report.

Reference Recommendations:

Linux interesting commands

Detailed description of Linux top command

Detailed Explanation of Linux sar System Performance Analysis Command

Perf-Linux System Performance Tuning Tool

Linux free Command: The Difference between buffer and cache

The Linux expect command does not require password entry

18 Command Line Tools for Linux Performance Monitoring