This is the first blog to introduce the configuration environment when I first worked. I have no experience in blogging, so it may be messy. I hope you can include more.
1、 Common instructions
- -EQ / / equals
- -NE / / not equal to
- -GT / / greater than
- -LT / / less than
- Ge / / greater than or equal to
- Le / / less than or equal to
2、 Common commands for processing directory
- Ls: List directory and file name
- CD: switch directory
- PWD: displays the current directory
- MKDIR: create a new directory
- Rmdir: delete an empty directory
- CP: copy file or directory
- RM: remove file or directory
- MV: move files and directories, or modify the names of files and directories
3、 Linux content view
- Cat displays the contents of the file from the first line
- TAC is displayed from the last line. You can see that TAC is written in reverse of cat!
- NL display, the output line number by the way!
- Show the contents of the file page by page
- Less is similar to more, but better than more, it can turn the page forward!
- Just look at the first few lines
- Tail only looks at a few lines of tail
4、 Change file properties:
Chgrp: change file group
Chgrp [- R] group name file name
Chown: change the owner or group of the file
Chown [– R] possessive name file name Chown [- R] generic name: generic group name file name
- Chmod: change 9 attributes of file
There are two ways to set Linux file attributes, one is number, the other is symbol.
There are nine basic permissions for Linux files. They are owner / group / others, and each has its own read / write / execute permissions.
Let’s review the data just mentioned above: the permission character of the file is: ［ – rwxrwxrwx ］, and the nine permissions are in a group of three! Among them, we can use numbers to represent each authority. The score comparison table of each authority is as follows:
The scores of the three permissions (R / w / x) of each identity (owner / group / others) need to be accumulated. For example, when the permission is: [- rwxrwx —], the score is:
- owner = rwx = 4+2+1 = 7
- group = rwx = 4+2+1 = 7
- others= — = 0+0+0 = 0
5、 Account management of Linux system
1. To add a new user account, use the useradd command. The syntax is as follows:
Useradd option user name
- -C comment specifies an explanatory description.
- -D directory specifies the user’s home directory. If this directory does not exist, the – M option is used to create the home directory.
- -G user group specifies the user group to which the user belongs.
- -G user group, which specifies the additional group to which the user belongs.
- -S SHELL file specifies the login shell of the user.
- -U user number specifies the user number of the user. If you have the – O option at the same time, you can reuse the identification number of other users.
- user name:
Specify the login name of the new account.