See file permissions :
ls -l example.txt
#output
-rw-r--r-- 12 linuxize users 12.0K Apr 8 20:51 example.txt
|[-][-][-]- [------] [---]
| | | | | | |
| | | | | | +-----------> 7. Group
| | | | | +-------------------> 6. Owner
| | | | +--------------------------> 5. Alternate Access Method
| | | +----------------------------> 4. Others Permissions
| | +-------------------------------> 3. Group Permissions
| +----------------------------------> 2. Owner Permissions
+------------------------------------> 1. File Type
What is chmod in Linux:
in UNIX OSes, chmod is a command to change files and directories permissions.
chmod stands for “change mode”.
one of the most important reasons for Linux to be on the list of safe OSes is that every user has their own permission for each file and folder.