Linux Tutorial | File Permission in Linux | Linux File Permissions Part-1

What is POSIX Permissions ?
POSIX permissions are the standards that define how Unix interacts with applications. Among other things, POSIX permissions define a permission structure for accessing files and folders.


What are linux permissions and how can we understand them ?
Everything in linux is file or directory.And we have 3 levels of permissions on each file / directory and 3 types of permissions on each file / directory.

Three levels of permissions are:
user/owner – The Owner permissions apply only the owner of the file or directory, they will not impact the actions of other users.
group – The Group permissions apply only to the group that has been assigned to the file or directory, they will not effect the actions of other users.
all users – The All Users permissions apply to all other users on the system, this is the permission group that you want to watch the most.

Three types of  permissions :
read – The Read permission refers to a user’s capability to read the contents of the file.
write – The Write permissions refer to a user’s capability to write or modify a file or directory.
execute – The Execute permission affects a user’s capability to execute a file or view the contents of a directory.