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Today, I will talk to you about how to view system information in CentOS. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

View system information

One: check cpu

More / proc/cpuinfo | grep "model name" grep "model name" / proc/cpuinfo

If you feel the need to see more comfortable

The code is as follows:

Grep "model name" / proc/cpuinfo | cut-f2-d:

Well, linux's commands should be so familiar.

Two: check inside

The code is as follows:

[root@CentOS ~] # grep MemTotal / proc/meminfo [root@CentOS ~] # grep MemTotal / proc/meminfo | cut-f2-d: [root@CentOS ~] # free-m | grep "Mem" | awk'{print $2}'[root@CentOS ~] # free-m

Three: check whether the cpu is 32-bit or 64-bit

View CPU digits (32 or 64)

The code is as follows:

[root@CentOS ~] # getconf LONG_BIT [root@CentOS ~] # echo $HOSTTYPE [root@CentOS ~] # uname-a

Four: check the current version of linux

The code is as follows:

[root@CentOS ~] # more / etc/redhat-release [root@CentOS ~] # cat / etc/redhat-release

Five: check the kernel version

The code is as follows:

[root@CentOS ~] # uname-r

[root@CentOS] # uname-a

Six: view the current time

The code is as follows:

[root@CentOS ~] # date

Seven: view hard drives and partitions

The code is as follows:

[root@CentOS] # df-h

[root@CentOS ~] # fdisk-l

You can also view partitions

The code is as follows:

[root@CentOS home] # du-sh

You can see all the space occupied.

The code is as follows:

[root@CentOS home] # du / var/www-sh

You can see the size of this directory

Eight: check the installed software packages

Check the software packages installed when the system is installed

The code is as follows:

Cat-n / root/install.log

More / root/install.log | wc-l

Check which packages have been installed now

The code is as follows:

[root@CentOS home] # rpm-qa

[root@CentOS home] # rpm-qa | wc-l

[root@CentOS home] # yum list installed | wc-l

Strangely, however, the number of installation packages I have queried through rpm and yum is not the same. I can't find the reason.

Nine: view the keyboard layout

The code is as follows:

[root@CentOS home] # cat / etc/sysconfig/keyboard

[root@CentOS home] # cat / etc/sysconfig/keyboard | grep KEYTABLE | cut-f2-d =

Ten: check the selinux situation

The code is as follows:

[root@CentOS home] # sestatus

[root@CentOS home] # sestatus | cut-f2-d:

[root@CentOS home] # cat / etc/sysconfig/selinux

Eleven: check the ip,mac address

You can see mac, gateway and other information in the ifcfg-eth0 file.

The code is as follows:

[root@CentOS home] # ifconfig

[root@CentOS home] # cat / etc/sysconfig/network-scripts/ifcfg-Auto_eth0

[root@CentOS home] # cat / etc/sysconfig/network-scripts/ifcfg-Auto_eth0 | grep IPADDR | cut-f2-d =

[root@CentOS home] # ifconfig eth0 | grep "inet addr:" | awk'{print $2}'| cut-c 6-

[root@CentOS home] # ifconfig | grep 'inet addr:' | grep-v' 127.0.0.1'| cut-d:-f2 | awk'{print $1}'

View Gateway

The code is as follows:

[root@CentOS home] # cat / etc/sysconfig/network

View dns

The code is as follows:

[root@CentOS home] # cat / etc/resolv.conf

Twelve: view the default language

The code is as follows:

[root@CentOS home] # echo $LANG $LANGUAGE

[root@CentOS home] # cat / etc/sysconfig/i18n

Thirteen: check the time zone and whether to use UTC time

The code is as follows:

[root@CentOS /] # cat / etc/sysconfig/clock

Fourteen: view hostname

The code is as follows:

[root@CentOS /] # hostname

[root@CentOS /] # cat / etc/sysconfig/network

Configure the firewall

It is very necessary to configure iptables firewall under CentOS. Come on let's learn how to configure!

I mentioned firewall configuration in my blog.

Set the firewall in Linux, and take CentOS as an example, open the configuration file of iptables:

The code is as follows:

Vi / etc/sysconfig/iptables

Use the / etc/init.d/iptables status command to query whether port 80 is open, and if not, you can handle it in two ways:

1. Modify the vi / etc/sysconfig/iptables command to make the firewall open port 80

The code is as follows:

-A RH-Firewall-1-INPUT-m state-- state NEW-m tcp-p tcp-- dport 80-j ACCEPT

two。 Turn off / turn on / restart the firewall

The code is as follows:

/ etc/init.d/iptables stop

# enable start

# restart restart

3. Permanently turn off the firewall

The code is as follows:

Chkconfig-level 35 iptables off

/ etc/init.d/iptables stop

Iptables-P INPUT DROP

4. Open port 21 in active mode

The code is as follows:

Iptables-An INPUT-p tcp-- dport 21-j ACCEPT

5. Open the port between passive mode 49152 and 65534

The code is as follows:

Iptables-An INPUT-p tcp-- dport 49152 tcp 65534-j ACCEPT

Iptables-An INPUT-I lo-j ACCEPT

Iptables-An INPUT-m state-- state ESTABLISHED-j ACCEPT

Note:

Be sure to give yourself a way back, leaving a management port for VNC and a management port for SSh.

It is important to note that you must modify this file according to the situation of your server.

Restart iptables after all modifications:

The code is as follows:

Service iptables restart

You can verify that the rules are already in force:

The code is as follows:

Iptables-L

After reading the above, do you have any further understanding of how to view system information in CentOS? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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