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This article mainly explains the "Liunx system management common commands and skills", the content of the explanation is simple and clear, easy to learn and understand, the following please follow the editor's ideas slowly in depth, together to study and learn "Liunx system management common commands and skills"!

Common commands for linux to view hardware equipment and system information

1. System

The code is as follows:

# uname-a # View kernel / operating system / CPU information

# head-n 1 / etc/issue # View operating system version

# cat / proc/cpuinfo # View CPU information

# hostname # View computer name

# lspci-tv # list all PCI devices

# lsusb-tv # list all USB devices

# lsmod # list the loaded kernel modules

# env # View environment variables

2. Common commands for resource viewing

The code is as follows:

# free-m # View memory usage and swap area usage

# df-h # View the usage of each partition

# du-sh # View the size of the specified directory

# grep MemTotal / proc/meminfo # check the total memory

# grep MemFree / proc/meminfo # check the amount of free memory

# uptime # View system running time, number of users, and load

# cat / proc/loadavg # View system load

2. Common commands for disk and partition

The code is as follows:

# mount | column-t # to view the status of attached partitions

# fdisk-l # View all partitions

# swapon-s # View all swap partitions

# hdparm-I / dev/hda # View disk parameters (for IDE devices only)

# dmesg | grep IDE # check the detection status of IDE devices at startup

4. Commands commonly used in network management

The code is as follows:

# ifconfig # View the properties of all network interfaces

# iptables-L # View firewall settings

# route-n # View the routing table

# netstat-lntp # View all listening ports

# netstat-antp # View all established connections

# netstat-s # View network statistics

5. Common commands related to process

The code is as follows:

# ps-ef # View all processes

# top # Real-time display of process status

6. User-related common commands

The code is as follows:

# w # View active users

# id # View specified user information

# last # View user login log

# cut-d:-F1 / etc/passwd # View all users of the system

# cut-d:-F1 / etc/group # View all groups of the system

# crontab-l # View the current user's scheduled tasks

6. Service

The code is as follows:

# chkconfig-list # list all system services

# chkconfig-list | grep on # lists all started system services

7. Programs, software

The code is as follows:

# rpm-qa # View all installed packages

2. Use iptables to shield IP segments under linux:

Shield a single IP

The code is as follows:

Iptables-I INPUT-s 124.115.0.199-j DROP

Mask IP segment

The code is as follows:

Iptables-I INPUT-s 124.115.0 DROP 16-j

Iptables-I INPUT-s 124.115.3.0 Universe 16-j DROP

Iptables-I INPUT-s 124.115.4.0 Universe 16-j DROP

Block the entire IP segment

The code is as follows:

Iptables-I INPUT-s 124.115.0 DROP 8-j

Block several IP segments

The code is as follows:

Iptables-I INPUT-s 61.37.80.0 DROP 24-j

Iptables-I INPUT-s 61.37.81.0 DROP 24-j

Don't forget to save and restart the iptables service after execution. The above is how to use iptables to mask IP segments under Linux.

Unseal

The code is as follows:

Iptables-D INPUT-s 14.153.250.80 DROP 24-j

Iptables-D INPUT-s 14.153.250.80-j DROP

Prohibit all IP from accessing a port

The code is as follows:

Iptables-I INPUT-p TCP-dport 80-j DROP

3. Several methods for quickly emptying the contents of files:

The code is as follows:

$: > filename # where: is a placeholder and does not produce any output.

$> filename

$echo "" > filename

$echo / dev/null > filename

$echo > filename

$cat / dev/null > filename

At some point, you need to empty the contents of the file without deleting the file. For example, some log files (log.txt)

The command under linux is: true > log.txt

Test results:

The code is as follows:

Touch log.txt → # New File log.txt

Vi log.txt → # Editing File

Enter anything you want.

: wq! Enter → # Save exit

Cat log.txt → # View file contents

True > log.txt → # View the contents of the file

Thank you for your reading, the above is the content of "Liunx system management common commands and skills". After the study of this article, I believe you have a deeper understanding of the common commands and skills of Liunx system management, and the specific use needs to be verified by practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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