Optimized boot auto-load service
1) using the NTSYSV graphical tool: [] there is * for the start.
2) using the Chkconfig tool:
Chkconfig--list//View the default boot status for all services
Chkconfig--list Service Name//view the default startup state of a service
Chkconfig--level Run Level list service name On|off//can specify that a service is turned on or off
Linux Command classification
Internal command: Refers to some special instructions, also known as built-in (built-in) directives, that are integrated into the Shell interpreter program (such as bash).
External command: Refers to a Linux system to complete a specific function of the script file or binary program, each external command corresponds to a file in the system, is a command outside the Shell interpreter program. The Linux system must know the file location of the external command before it can be loaded and executed by the shell.
Format of the Linux command line: command word [options] [parameters]
1) command word: The command name is the most critical part of the entire command.
2) The function of the option is to adjust the specific function of the command, and determine how the command executes.
Different command words can use different options (number of options and content).
The number of options can be multiple or omitted. When you use multiple options at the same time, the options are separated by a space. If you do not use the option, the default function of the command Word will be executed.
? When using the option of a single character, the "-" symbol (the half-width minus sign) is generally used before the option to boot, called the short format option, such as "-L". Multiple single-word check items can be grouped together, such as "-al" equivalent to "-a-l".
When using options with multiple characters, the "--" symbol (two-half-width minus sign) is generally used before the option to boot, called the long format option, such as "--help".
3) Parameters: The command parameter is the processing object of the command word, usually the command parameter can be a file name, directory (path) name or user name, and so on.
Get command Help
1) using the Help command is a helpful look at the commands inside each shell.
2) Use "--help" option for most Linux external commands, you can display the corresponding command Word format and options and other help.
3) Man Manual (manual page) is one of the most commonly used online help forms in Linux systems.
Columns such as: [[email protected] ~] #man ls | Col-b > Lshelp.txt
In this sake, where Col is a command program that filters some special control characters in the text, and also uses the "|" and the ">" symbol, which is the two special functional applications in the shell environment, called "Pipe", "redirected Output", respectively.
Pipe: Using the vertical bar symbol "|" Indicates that the screen output of the preceding command is used as the Action object (input) of the following command. It's like a pipe, from which you plug in content and come out from the other end.
REDIRECT output: Using the greater than symbol ">" means that after the previous command executes successfully, its screen output will be saved to the file specified behind the ">" (overwrite), instead of being output directly to the screen. ">>" means append does not overwrite.
Some common commands and functions
command Example function
Uname-r View the current Linux kernel version information used
Cat/proc/cpuinfo View current host CPU model, specifications and other information
Cat/proc/meminfo View memory information for the current host
Hostname View the full name of the current host
Ifconfig eth0 View address information for the 1th Ethernet card
Shutdown-h now shutdown
Shutdown-r now restart
PWD Displays the location of the working directory where the user is currently located
cd-changing the user's working directory to a different location
? -Current Working directory
?? -Top level directory of the current directory
~ User name-Specifies the user's host directory, omitting the user name for the current user
-Previous working directory
Ls Displays the contents of the directory, including information about the properties of subdirectories and files, etc.
-l display in long format, including information such as permissions, size, last update time, and more
-a displays all subdirectories and files, including hidden directories and hidden files
-D Displays the properties of the directory itself instead of displaying the contents of the directory
-H displays size in units such as K, M, and not the default byte
Du statistics Specifies the size of disk space occupied by a directory (or file)
-a-statistics include all the files, not just the statistics directory
-h-display statistical results in units such as K, M, etc.
-s-only the total size of the statistics parameter, not the size of subdirectories, files
Touch creates an empty file
MkDir used to create a new empty directory
-p-creating nested Multilayer catalogs at once
ln establishes a linked file (a shortcut like Windows) for a file or directory
-s-Creating a soft link
CP Copy files or directories
-f-overwrite a file or directory with the same name without a reminder and directly force replication
-i-when overwriting a file or directory with the same name reminds the user to confirm
-p-preserve the permissions of the source file, the owner and the time tag when copying
-r-when replicating directories, which means recursively copying all files and subdirectories
RM is used to delete the specified file or directory
-f-Delete a file or directory without a reminder, and force delete directly
-i-remind users to confirm when deleting files or directories
-r-when deleting a directory, indicating recursive deletion of the entire directory tree
MV transfers the specified file or directory to the location, if the target location is the same as the source location, the effect is equivalent to renaming a file or directory
Which find the directory where the command files that the user executes are stored
Find file or directory
-name-based on the name of the target file, you can use "*" and "? "Pass-the-lose character
-size-search based on the size of the target file
-user-lookup based on whether the file belongs to the target user
-type-Search by file type (F/D/B/C)
View and retrieve files
1) Cat command-displays and connects the contents of the (concatenate) file
Example: View Cat/etc/sysconfig/network-scripts/ifcfg-eth0
Device=eth0//First NIC
Onboot=yes
Bootproto=none//define NIC, static or none; dynamic DHCP.
netmask=255.255.255.0//Subnet mask
ipaddr=192.168.4.11//ipv4 Address
gateway=192.168.4.254//Gateway
Type=ethernet//Type: Ethernet
View the contents of multiple files Cat/etc/redhat-release/proc/version
The former records the release information of Rhel system, the latter records the system kernel and development environment, time and other information.
2) More and less commands-paging to view the contents of a file
For example, split-screen view of the contents of the More/etc/httpd/conf/httpd.conf (Web site configuration file).
In this reading interface, you can press ENTER to scroll down by line, press SPACEBAR to scroll down a screen, press the B key up one screen, press the Q key to exit and return to the original command environment.
The more command can be combined with a pipe symbol "|" In addition to viewing the contents of a file in a split screen. Split-screen View the output information when the command is executed, which is particularly useful in situations where the command output is large.
For example, paging through the/etc/directory has those configuration files with the extension ". conf". The command is as follows:
ls–lh/etc/. conf | more
3) Head and Tail command-view part of the file at the beginning or the end
The "Head-n" head is the header (n is the exact number of rows). "Tail-n" tail look at the end, with "-F" to track dynamic updates.
For example: View the user account file/etc/passwd beginning from line 1th to line 4th of the content. Head-4/etc/passwd
For example: View the last ten lines of the system's public log file/var/log/messages and trace the contents of the new record in the file at the end (press CTRL + C to terminate). Tail-f/var/log/messages
Statistics and retrieval of file contents
1) WC command-information about the number of words in the statistics file content (Word count), number of lines, and so on
Parameters:?-c: Number of bytes in the content of the statistics file
?-L: Statistics the number of rows in a file's contents
?-W: Count the number of words in the file contents
The three options above are used by default when using the WC command without any parameter options.
For example, see how many rows are in the/etc/passwd file. Wc-l/etc/passwd
To count the total number of files in the/etc/directory that have the extension ". conf", you can go through the "Find/etc-name"The. conf "" command identifies the location of the file that matches the condition, and each line records the contents of a file. Find/etc-name "*.conf" | Wc-l
2) grep command-retrieve and filter file contents
Parameter:?-I: Case is ignored when finding content (Lgnore).
(option)?-V: Reverse lookup (invert), which outputs rows that do not match the lookup criteria.
For example: Execute "grep" ftp "/etc/passwd" command, in the account file/etc/passwd to find the line containing "FTP" string, actually output the user account named FTP information.
For example: Displays the lines that begin with "#" in the/etc/vsftpd/vsftpd.conf file, and what is outside the empty line. ($ represents a blank line). The command is as follows:
Grep-v "^#"/etc/yum.conf | Grep-v "^$"
Using the compression and decompression tools
1) gzip and Gunzip commands
Compressed files made with GZIP have the default extension of ". Gz". When making a compressed file, using the "9" option increases the compression ratio, but it can take more time when the file is larger.
gzip file or directory this is a. GZ compression. Unzip: Gzip–d file. gz or gunzip file. gz
2) bzip2 and BUNZIP2 commands are used in the same way as gzip, gunzip commands, and compressed files made with BZIP2 have the default extension ". bz2"
Several options for using the TAR Archive and release tool
?-C (lowercase): Creates (create), Tar-formatted package files.
?-C: Specifies the target folder to release when extracting.
?-F: Indicates the use of an archive file.
-j: Call the BZIP2 program for compression or decompression.
?-p (lowercase): Preserves file and directory permissions while packaging.
?-P: Preserves the absolute path to files and directories when packaged.
?-T: List to view the files within the package.
?-V: Output details (verbose).
?-X: Unzip the package file in. tar format.
?-Z: Call the gzip program for compression or decompression.
Command format: tar [options]??? Archive and compress file names for source files or directories that need to be archived???
For example, in the current directory, an archive compressed package named Sysfile.tar.gz is generated.
Tar zcf sysfile.tar.gz/etc/boot//sysfile.tar.gz archive for boot compression of etc
To use archive compression packages in the format ". tar.bz2", change the "-Z" option to "-j" option.
Recover data from archive file in lost format
tar [options]??? Archive and Compress file names [-C (uppercase) target directory]
For example: Restore data from the backup usershome.tar.bz2 and release it to the root directory (overwriting the existing file).
Tar jxf/tmp/usershome.tar.bz2-c/
Set the command alias for example: Point VI to the VIM program command as follows.
Alias vi= '/usr/bin/vim '
Which-a vi vim View the location of the command
VI Editor Mode of operation:
Command mode input mode last line mode
Basic operations in the command mode
1) Mode switching
? A: Insert content after the current cursor position.
? A: Inserts the content at the end of the line where the cursor is located (end of line).
? I: Insert content before the current cursor position.
? l: Inserts the content at the beginning of the line where the cursor is located (at the beginning).
? o: Inserts a new line after the cursor line.
? O: Insert a new line in front of the line where the cursor is located.
2) Move cursor
Page
? Use the PAGE DOWN key or the CTRL+F key to turn down a whole page of content.
? Use the page UP key or the CTRL+B key to flip up a full page of content.
The cursor moves up or down.
Quick Jump in line
? Press the Home key or the ^ key, the number 0 key to quickly jump to the beginning of the line.
? Press the end key or the key to quickly jump the cursor to the end of the line.
Quick Jump between rows
? Use the key command 1G or GG to jump to the 1th line of the file contents.
? Use the key command G to jump to the last line of the file.
? Use the key command #g to jump to the # # line in the file (where the "#" number is replaced with a specific number).
Last row use
": Set nu" command to display line numbers ": Set Nonu" command to suppress line numbers.
3) Copy, paste and delete
Delete operation
? Use the X key or the DEL key to delete a single character at the cursor.
? Use the key command DD to delete the current cursor line, using the form of #dd can also be deleted from the beginning of the cursor # line content (where "#" is replaced with a specific number).
? Use the key command d^ to delete all characters before the current cursor to the beginning of the line.
? Use the key command d$ to delete all characters at the end of the line at the current cursor.
Copy operation
? Use the key command yy to copy the contents of the entire row of the current line to the Clipboard, using the form of #yy, you can also copy the # line content (where the "#" number is replaced with a specific number) starting at the cursor. The copied content needs to be pasted before it can be used.
Paste operation
In the VI editor, the previous deleted or copied content will be saved to the Clipboard buffer, press the P (lowercase) key to paste the contents of the buffer at the cursor position, and press the P (uppercase) key until the cursor position.
4) Find File contents
In command mode, you can enter the specified character channeling after pressing the/key, starting at the current cursor and looking backwards (? Looking forward).
5) Retreat Edit and save and exit
When editing the contents of a file, it is sometimes necessary to undo some of the errors of editing, which you can use by pressing the U,u key.
When you save the current file contents and exit the VI editor, you can press the ZZ command.
Basic operations in the last-line mode
W, users, who--query the current host user logon situation
Managing the properties of directories and files
In the security model of the Linux file system, two properties are assigned to files (or directories) in the system: access rights and file owners, referred to as "permissions" and "Attribution". Among them, access rights include read, write, executable three basic types, attribution includes the owner (the user account that owns the file), belongs to the group (the group account that owns the file). The Linux system controls the process by which the user accesses the data based on the access rights and attribution of the file or directory.
To view the properties of a directory and a file
For example: [[email protected] ~]# LS-LD/ETC/ETC/PASSWD//List Detailed properties of/etc/directory and/etc/passwd file
Drwxr-xr-x. 119 root Root 12288 May 9 17:33/etc
-rw-r-r--. 1 root root 1678 May 9 17:33/etc/passwd
In the above output information, the data of the 3 and 4 fields respectively represents the owner and genus of the file (or directory), and the "/etc" and "/etc/passwd" files listed above belong to the root user, the root group, and the data in the 1th field represents the access rights of the file (or directory), such as " Drwxr-xr-x "and"-rw-r-r--".
The permission fields are made up of four parts, each of which has the meanings described below.
The 1th character: Indicates the type of the file, which can be D (directory), B (block device file), C (character device file), "-" (normal file), letter "L" (linked file), etc.
? 2nd ~ characters: Represents the owner (user) of the file's access rights to the file.
? The 5th to 7th character: represents the user (group) access to the file within the group.
? The 8th to 10th character: represents the access rights of any other user (other) to the file.
? 11th character: Here's "." There is no need to be concerned about SELinux.
When you represent a user or other user who has access to the file, it uses three different permission characters: R, W, X, respectively, which are readable, writable, and executable. If you need to remove the corresponding permission, use "-" to indicate. For example, the root user has a readable, writable, executable full permission (r W x) for the "/etc" directory, and any other user has only a readable executable permission (r–x) for the "/etc" directory, and the root user has a readable, writable permission (r W-) for the "/etc/passwd" file. Each user within the root group has only read access to the "/etc/passwd" file (r--).
权限 文件 目录
(4) R viewing the contents of a File View directory contents (display subdirectories, file list)
(2) W Modify the contents of the file to modify the contents of the directory (new, move, delete files or subdirectories in the directory)
(1) x Execute the file (program or script) Execute C d command to enter or exit the directory
Set permissions for directories and files
When you use the chmod command to set permissions for a file or directory, the basic command format is:
Chmod [Agoa ...] [+-=] [rwx] File or project .....
Or
Chmod nnn file or directory ...
You need to set the permissions for all subdirectories and files in a directory to the same value, and chmod is easily implemented with the "-r" option. Example: Chmod-r 644/var/ftp/pub
In the above format, the character combination "[Ugoa ...] [+-=] [RWX] "or a combination of numbers" nnn "represents the permission mode to be set. where "nnn" is the specific permission value that needs to be set, such as "755" "644" and so on; "[Ugoa ...] [+-=] In the form of [rwx], the meanings and usages of the three components are described below.
?“ Ugoa "indicates the user class to which this permission setting is directed. "U" represents the owner of the document, "G" represents the user within the group, "O" represents any other user, "A" represents all users (sum of u, G, O).
?“ +-= "represents an action action that sets permissions. "+" means to increase the appropriate permissions, "-" means to reduce the corresponding permissions, "=" to set only the corresponding permissions.
?“ R W X "is a character combination of permissions and can also be used for splitting, such as" R "," R X ", and so on.
To set the attribution of directories and files
Need to set the file or directory attribution, mainly through the chown command. You can set only the owner or the genus Group, or you can set both the owner and the genus. Use the basic format of the Chown command.
Chown owner [: [Genus]] file or directory .....
When you set the owner and the group, the user name and group name are separated by a colon ":". If you only set up a group, you use the form ": Group name". If you only need to set the directory or the owner of the file, directly to the user name for attribution, recursive modification of directory attribution can be used with the "-r" option.
For example: Change the owner of the/var/ftp/pub/directory from root to FTP (the user FTP will have "R W x" permissions after the adjustment).
Chown-r ftp/var/ftp/pub
Change the owner of the Mymkdir file to daemon, the genus group to wheel.
Chown daemon:wheel/opt/wwwroot/
LINUX6 basic Commands
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
