Linux System Management-topic 02: Managing Good Files (1) _2.2 list file and file attributes _chmod_ls

? A user is a collection of permissions that can obtain system resources. Users in Linux can be categorized into three categories:

1. Root user (Root): Users with full system privileges;

2. Ordinary users: their access to the system is limited by a certain extent;

3. System users: Also known as virtual users, is to protect the system operation of users, generally not through the Shell login system.

? A user group is a collection of users (user) with the same characteristics.

-RWXR-XR--. 1 dev01 dgroup 116 September 12:42 helloworld.sh

Field 1-rw-rw-r-. Types and Permissions

Field 2 1 Number of connections

Field 3 DEV01 Owner

Field 4 Dgroup file group

Field 5 116 Size

Field 6 September 27 12:42 Modified Time

Field 7 helloworld.sh file name

? There are 7 types of files in Linux, and here are the 7 types of files and their type code characters:

1.-General Documents

2. D Catalog File

3. l Symbolic Link file

4. C-character Special device file

5. B Module Special Equipment file

6. P FIFO Pipeline File

7. S socket file

Usage: LS [option] ... [File] ...

Lists the FILE information (default is the current directory).

If you do not specify the-cftuvsux or--sort option, sort by letter size.

? -A does not hide any. Start the project? -a list except. And: Any item other than

? -C Sort by CTime (the file attributes or the last time the content changed); Use with-lt: Sort by ctime and show CTime; use with-L: Show CTime but sort by name.

? -d lists the directory itself instead of the files in the directory when the directory is encountered

? -F Plus indicator of file type (*/[email protected]| one)

? -H with-l output file size in an easy-to-read format (for example, 1K, 234M, 2G, and so on, by default, the unit is Byte)

? -I displays the inode number of each file

? -l list information in a longer format

? -N similar to-L, but lists UID and GID number

? -R sort to preserve order? -R Recursive Display subdirectory

? -s sort by file size

? -T sort based on mtime (last modified time for file content)

? -U Sort by atime (file last accessed time), used with-lt: sorted and displayed by access time, used with-L: Displays access time and sorts by file name.

Usage: chmod [options] ... mode [, Mode] ... File...

Or: chmod [options] ... Octal mode file ...

Or: chmod [options] ...--reference= reference file ...

Change the mode of each file to the specified value.

? --reference= reference files Use the mode of the specified reference file, not the specified permission value

? -R,--recursive to change all files and subdirectories recursively

Linux System Management-topic 02: Managing Good Files (1) _2.2 list file and file attributes _chmod_ls