Linux-File permissions

-rwxr-xr-x 1 root root 42304 Sep 4 18:30 test.log

2. The first part is the permissions of the file :
   • The first character indicates that the file is "directory, file or link file, etc."
     • D: Catalogue
     • -: File
     • L: Link File
     • B: Device interface available for storage
     • C: Serial port device, such as keyboard, mouse
   Rwxr-xr-x, three groups representing the permissions of the file owner (U), the same user group (g), and other non-user groups (O):
   • R: Readable, 4
   • W: Writable, 2
   • x: Executable, 1
   • rwxr-xr-x=755
4. To change file permissions:
   • chmod: Changing the permissions of a file
     • chmod [-CFRV] MODE directory or file
     • -C: report information when a change occurs
     • -F: Error message not output
     • -R: Working with directories and their subdirectories
     • -V: Display processing information
     Mode can be divided into:
     • chmod 777 File:file's permission is rwxrwxrwx
     • chmod a+x file: All users and Groups plus X permissions
     • chmod u=rw File: Change the permissions of the owner to RW
     • chmod g-x File: Remove the permissions of the user group from the Execute permission
   • chgrp: Changing the user group to which the file belongs
     • CHGRP [-CFRV] [group] File/directory
     • The meaning of each option is the same as above
     • CHGRP users file: Change the user group of file to users
     • Chgrp--reference=file1 file2: Make the File2 user group the same as File1
   • chown: Changing the file owner
     • chown [-cfrv][owner][:[User Group]] File/directory
     • Chown mail:mail File
     • Chown:mail file
     • Chown--reference=< files or directories > files or directories

Linux-File permissions