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This article introduces the knowledge of "what are the commonly used Linux commands?" in the operation of actual cases, many people will encounter such a dilemma, and then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Shutdown: poweroff or shutdown-h now or init 0

Restart: reboot or shutdown-r now or init 6

Turn off x-window:init 3

Start x-window:init 5 or start x

Check the IP address: ifconfig

Linux kernel version: uname-r

Basic command

1. Check a port number. Command: netstat-pan | grep 80

2. Check whether the linux version is centos or redhat. Command: cat / etc/redhat-release

3. Zip folder compression command: zip-r compression final file name. the name of the folder to be compressed by zip

Firewalls

1. Start the firewall, command: service iptables start or / etc/init.d/iptables start

2. Turn off the firewall. Command: service iptables stop or / etc/init.d/iptables stop

3. Restart the firewall, command: service iptables restart or / etc/init.d/iptables restart

Tomcat

1. Start tomcat and go to the bin directory under the tomcat installation directory to execute. / startup.sh

2. Stop tomcat and go to the bin directory under the tomcat installation directory to execute. / shutdown.sh

3. Delete the log command and go to the logs directory under the tomcat installation directory to execute rm-rf *. *

1. Terminate command: ctrl+c

two。 End input: ctrl+d

3. View file systems: how df-h Linux views file systems (disk usage)

4.LAMP series:

Restart MySQL:/etc/init.d/mysqld restart

Restart Apache: / etc/init.d/httpd start

The configuration file path of Apache: / etc/httpd/conf/httpd.conf

PHP profile path: / etc/php.ini

Restart the network service: service network restart

Modify site directory permissions:

Chmod-R 777. / ecshop

Chown apache:apache. / ecshop

Bin basic command

Boot bootstrap file, LINUX kernel

Dev device file

Etc system profile

Home user home directory

Initrd initial RAM disk boot support (used during boot)

Lib shared library, kernel module

Lost+found stores recovered files (if such files are found after a file system check)

Media mount points for removable media such as DVD and floppy disks

Mnt is usually used as a mount point for local and remote file systems

Additional software packages added by opt

Proc kernel information, process control

Home directory of the root superuser (ROOT user)

Sbin system commands (most can only be used by ROOT users)

Srv stores the data of system services, and part of the data of system services is currently stored in var

Sys real-time information related to the devices used by the kernel

Tftpboot Network Boot support

Tmp temporary file

Usr's second major software file hierarchy

Var variable data (such as logs); buffered (spooled) files

# hostname View computer name

# dmidecodegrep Manufacturer View Server manufacturer

# dmidecodegrep Product Name to view server model

# grep model name proccpuinfo to view CPU information

# getconf LONG_BIT check whether CPU is 32-bit or 64-bit

# cat proccpuinfogrep physical idsortuniqwc-l View the number of physical CPU

# cat proccpuinfogrep cpu coresuniq View the number of CORE in each physical CPU (i.e. the number of cores)

# cat proccpuinfogrep processerwc-l check the number of logical CPU. If the value is not equal to (number of CPU × number of cores), hyperthreading is supported.

# dmidecode-t memory to view memory details

# cat procmeminfo to view memory information

# swapon-s view all swap partitions

# free-m looks at the total memory, used, free, total memory shared by multiple processes, total memory used, total memory available, and swap partitions.

Note:-+ bufferscache equals used-buffers-cachedfree+buffers+cached. If the swap partition is used too much, it means that more physical memory is needed.

# dmesg grep 'Vendor' to view hard disk, optical drive and other information

# hdparm-I devsda displays the parameter information of the hard disk

# fdisk-l View the total capacity of the hard disk

# df-hT to view the usage of each partition

# du-sh etc to view the size of the specified directory

# du-csk sort-rn head-n 10 find the top 10 files or directories that take up the most space in the system.

# isostat-x 1 5 View hard disk IO performance (yum-y install sysstat)

Note: if the% util is close to 100%, there are too many IO requests, the IO system is fully loaded, and there may be a bottleneck on the disk. If the idle is less than 70%, there is more wait,IO in the reading process and the pressure is greater.

# uptime check the current time of the system, the running time of the host, the number of user connections, and the average load of the last 15 minutes of the system.

# vmstat 1 4 View the process status, memory usage, virtual memory usage, disk IO, interrupt, context switch, CPU usage of the system.

Note: if r is often greater than 3 or 4, and id is often less than 50, the load on CPU is very heavy. Bi and bo are not equal to 0 for a long time, indicating insufficient memory. Disk is often not equal to 0, and queues in b are greater than 2 or 3, indicating poor performance of IO.

# uname-a view kernel operating system CPU information.

# cat procversion displays the kernel version

# head etcissue View operating system and version

# file sbininit checks whether the system is 32-bit or 64-bit.

# lsmod to view the relevant modules loaded by the system

# lspci lists all PCI devices

# lsusb lists all USB devices

# cat procloadavg to view system load disks and partitions

# hdparm-I devhda View disk parameters (for IDE devices only)

# env View Environment variable Resources

# mount column-t to view the attached partition status

# mount devcdrom mntcdrom mounts the CD-ROM drive

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

# w View active users

# whoami View current user

# id root to view specified user information

# finger root View ROOT user details

# runlevel to view the current running status

# ps-ef to view all processes

# top displays process status in real time

# last View user login log

# lsof-i22 to see which programs occupy port 22

# cut-d-F1 etcpasswd to view all users of the system

# cut-d-F1 etcgroup View all groups of the system

# crontab-l View the current user's scheduled task service

# kill-9 3820 forcibly end a process with an ID of 3820

# killall apache ends the apache process

# xkill clicks on the kill process in the graphical interface

# skill (pkill)-kill-u root logs out of all root logins

# pkill (skill)-kill-t pts2 logs out users of this login type pts2

# chkconfig-list lists all system services

# chkconfig-- list grep 2on lists all started system services

# ifconfig eth0 10.8.1.2 netmask 255.255.255.0 temporarily configure IP and subnet mask

# ifconfig eth0 down deactivate the network card

# ifconfig eth0 hw ether 000c2888fd26 modifies MAC address

# ifconfig eth0 up enable Nic

# vi etcsysconfignetwork-scriptsifcfg-eth0

DEVICE=eth0

BOOTPROTO=static

BROADCAST=192.168.1.255

HWADDR=000C292C2AE2

IPADDR=192.168.1.101

NETMASK=255.255.255.0

NETWORK=192.168.1.0

GATEWAY=192.168.1.1

ONBOOT=yes

# sudo etcinit.dnetwork restart

# cat etcsysconfignetwork View hostname

# cat etchosts View CVM hosts

# cat etcresolv.conf View DNS Server

# route add default gw 10.8.1.1 configure Gateway

# route add-net 172.16.6.0 netmask 255.255.255.0 gw 172.16.2.25 temporarily add static routes

# echo 172.16.6.024 via 172.16.2.25etcsysconfignetwork-scriptsroute-eth0 permanently add static routes

# iptables-L (netstat-r) View Firewall Settings

# route-n View the routing table

# netstat-lntp view all listening ports

# netstat-antp to view all established connections

# netstat-s View Network Statistics

# nslookup (dig www.baidu.com)

Etcgroup and etcpasswd and etcshadow group information and account information and password information

# useradd-d homeadmin-s binbash-u 33-G root-M admin add administrator group user admin

# usermod-G roots aa adds aa to the roots group

# userdel-r admin removes the admin user and its home directory

# passwd admin change password

# passwd-l admin Lock users

# passwd-u admin unlocks users

# groupadd roots create group roots

# groupdel roots Delete Group roots

# groupmod nroot roots modify group name

# gpasswd-A root roots add root to roots group

# gpasswd-d root roots moves root out of the roots group

# chmod 777 etcsudoers modify sudoers file permissions

# chown adminroot install.log changes the owner of install.log to admin and the group to root

# chgrp admin install.log changes the group of install.log to admin

In fact, only ROOT should have permission to run passwd, because it has permissions of s in rws, so ordinary users have permission to run it.

The last three digits of tmp permissions are rwt, and this t stands for sticky bit permissions. Any user can write, but other people's data is not allowed to be deleted.

If a file is set to the SUID or SGID bit or SBIT bit, it will be represented in the executable bits of the permissions of the owner or the same group of users or other users, respectively. For example:

1.-rwsr-xr-x (4755) indicates that the executable bits in SUID and owner permissions are set

2.-rwSr--r-- (4644) indicates that the SUID is set, but the executable bit in the owner permission is not set

3.-rwxr-sr-x (2755) indicates that the executable bits in SGID and user permissions in the same group are set

4.-rw-r-Sr-- (2644) indicates that SGID is set, but the executable bits in the same group of user permissions are not set

5.-rw-rw-r-t (1665) indicates that the executable bits in SBIT and other user permissions are set

6.-r--r--r-T (1444) indicates that the SBIT is set, but the executable bits in other user rights are not set.

SUID,SGID,SBIT is denoted by "4" and "2" respectively, and its position is placed at the front.

# chmod u ±s filename sets or removes the SUID bit

# chmod g ±s filename sets or removes SGID bits

# chmod o ±t tmp sets or removes stickiness

# chattr + a tmpsb.sh files are only allowed to be added, not modified or deleted.

# chattr + I tmpsa.sh archives do not allow add, modify and delete operations.

# lsattr tmpsb.sh

# umask 002

The default permissions for files and directories are 666,777,and 0022 for umask, so the default permissions for file and directory creation are 644,755.

UBUNTU

# apt-get update download but not update

# apt-get upgrade download and update

# apt-get dist-upgrade Smart Update Software

# apt-get install xipmsg installation of Flying Pigeon

# apt-get install wine1.2 install wine

# apt-get install (nvidia-glxxorg-driver-fglrx) (nvidia-settingsfglrx-control) to install the nvidia or ati display driver

# sudo gedit etcX11xorg.conf file content: Driver fglrx or Driver nvidia

# glxgears or fgl_glxgears testing 3D acceleration

# apt-get remove apache remove package can contain configuration file

# apt-get remove-purge apache removes packages and configuration files

# apt-get clean clear cache package

# apt-cache-n search games grep kde searches games-related KDE packages by package name

# apt-cache-n search ^ kde searches for packages whose names begin with KDE ($ends with KDE)

# apt-cache showpkg mysql-server-5.0 to view information about packages

# rpm-qa to view all installed software packages

# rpm-ivh apache.rpm installation

# rpm-Uvh apache.rpm upgrade

# rpm-e apache Uninstall

# rpm-Va verifies that all rpm packets have been tampered with

# tar czvf dirname.tgz dirname compressed dirname directory

# tar tzvf dirname displays the contents of compressed archive files

# tar xzvf dirname.tgz-C ~ source decompress the file to the source directory

# .configure configuration

# make compiles the software

# make install installation

# make clean clears previously compiled executables and configuration files

# make distclean clears all generated files

# make uninstall delete software

# vi etcinittab modify the login interface after startup

# remember to execute sync to save cached data to the hard disk before poweroffshutdownhaltreboot execution

# shutdown-k now shutdown now! Send messages to all users.

# init 0356 shutdown text mode graphic mode restart

# loginlogout login and logout computer

# ls-la homea

# touch filename create File

# mkdir dirname create directory

# rm-rf dirname deletes a directory and all its files

# last displays login and logout for all users

# lastb shows all failed and incorrect logins

# cat ~ .bash _ history View commands that have been run by the current user

# vi etcsudoers edit by I, join admin ALL= (ALL) ALL, press ESC, enter wq!

Which searches through the user's path variables, locate and whereis search the database, and find searches hard disk files directly.

More linux commands https://www.yisu.com/linux/

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