Utility Collection Linux Command memo

System operation

#使用shutdown命令马上重启系统
[Email protected] ~]# Shutdown–r now
#使用shutdown命令马上关闭系统
[Email protected] ~]# Shutdown–h now
#使用shutdown命令设置在15分钟以后自动重启系统
[Email protected] ~]# shutdown–r +15

Show online login user who

Show current Operation user WhoAmI

Display host name hostname

Display System Information uname

Dynamic display of currently consuming resources up to process information top

Open service ntpd Start

View service status Services NTPD status

Close Service ntpd Stop

Boot from Chkconfig ntpd on

SSH login ssh [email protected]

Network conditions

View network conditions Ifconfig

Test network Connectivity Ping

Show Network status information Netstat-tap | grep MySQL

See if the port is occupied netstat-ant |grep 3306

View Process Ps-ef | grep MySQL

Kill the process, you can first use the PS or top command to see the process ID, and then kill the process kill-9 1234 process number

Shut down the firewall systemctl stop iptables (CentOS7)

File operations

View your current working directory pwd

Directory Jump cd/usr/local go to the local folder

Return to the previous level CD.

Return to last catalog CD-

Find/-name file1 from '/' to the root file system to search for files and directories

Create folder mkdir-p XXX Create directory, if no parent directory, create p (parent)

Create file Touch xxx Create an empty file

Create a file with content echo xxx

View files Cat xxx

View all files and directories under directory structure including hidden A (all) Ls-al xxx

Copy the file cp/usr/local/abc.txt/usr copy the abc.txt to the/usr directory

Delete files Rm-rf xxx with-R for recursive deletion, can delete subdirectories and files with-F for forced deletion

Move or rename mv xxx xxx1

Sometimes without permission, so you have to add sudo

sudo mv Abc.jar

Edit File Vi/etc/network/interfaces

Then press the I key to enter the input mode

After editing, press the ESC key to save the exit file directly: Wq

File Append Content
Cat Authorized_keys_from_yang >> Authorized_keys

Package operations

Extracting Files TAR-ZXVF hadoop.tar.gz

User group actions

Store user account/etc/passwd

Storage group Account/etc/group

Store password for user account/etc/shadow

Password to store user group account/etc/gshadow

SU user switches the user, loads the configuration file. You may need to enter a password after BASHRC

Groupadd group_name Create a new user group

Useradd-c "Name Surname"-G admin-d/home/user1-s/bin/bash user1 create a user who belongs to the "admin" user group

File Permission Actions

Chown–r hadoop:hadoop Hadoop #将文件夹 "Hadoop" Read permissions assigned to Hadoop users

chmod 0755 File # Changes files permissions to-rxwr-xr-x
chmod g+w File # Adds a user group writable permission to files ' permissions

user and user groups for changing files

sudo chown [-r] Owner[:group] {file| Directory}

For example: Also take jdk-7u21-linux-i586.tar.gz as an example. belongs to user Hadoop, group Hadoop

You want to switch the users and groups to which this file belongs. You can use commands.

sudo chown-r root:root jdk-7u21-linux-i586.tar.gz

redirect

Description: The standard input device in a Linux system is the keyboard, the standard output device is the screen, but in some cases we want to be able to read data from other input devices other than the keyboard, or to send the data to other output devices outside the screen, which is called redirection. The input-output redirection in the shell is primarily based on redirection symbols, which are usually a file.
Input redirection: Input redirection is the way that incoming input in a command is redirected from the default keyboard to the specified file, and you need to use the < redirection operator. The command "WC < F1" means that the information of the F1 file is used as input to the WC command.
Output redirection: Output redirection redirects the output of the command to a file instead of being displayed on the screen. Output redirection uses the ">" or ">>" operators, respectively, to overwrite and append files. The file specified later in the ">" redirect if it does not exist, the file is created in the command execution and the command results are saved to the file. If the file specified after the ">" redirect is present, the command executes to empty the contents of the file and saves the command result to the file.
#查看 the contents of the/etc/passwd file and save the output to the Pass.txt file.
[Email protected] ~]# cat/etc/passwd > Pass.txt
After executing the command, a file named Pass.txt is generated in the current directory, and the contents of the file are the results of the "cat/etc/passwd" command execution.
The >> redirect operator redirects the result of the command execution and appends it to the end of the specified file, without overwriting the contents of the file.

#查看 the following 3 lines of the/etc/shadow file and append the output results to the Pass.txt file.
[Email protected] ~]# tail-3/etc/shadow >> pass.txt

Pipeline

Description: Pipe symbol "|" Used to connect the left and right two commands, the "|" The execution result of the left command as "|" The input to the right command, so "|" It is like a pipe connected to the left and right two commands, and in the pipeline to achieve the data from a to-go transmission.
#分页显示 the details of all files and subdirectories in the/etc directory.
[Email protected] ~]# Ls-lh/etc | More
#显示 the details of all files and subdirectories that contain the "NET" keyword in the/etc directory.
[Email protected] ~]# Ls-lh/etc | grep net
-rwxr-xr-x. 1 root root 1.3K April auto.net
-rw-r--r--. 1 root root 74 May issue.net
-rw-r--r--. 1 root root 767 November Netconfig
-rw-r--r--. 1 root root 58 May Networks
Drwxr-xr-x. 2 root root 4.0K January 8 19:14 xinetd.d
#统计一下 the number of files ending with ". conf" in the/etc directory.
[Email protected] ~]# Ls-l/etc/*.conf | Wc–l 44
#查看 the/etc/httpd/conf/httpd.conf file except for lines and blank lines that begin with "#".
[Email protected] ~]# grep-v "^#"/etc/httpd/conf/httpd.conf | Gerp–v "^$"

Utility Collection Linux Command memo