[ Thanks to Mayank
for this link. ]
“In a secure multi-user environment like Linux, file
permissions access rights are defined. However, these access rights
can cause problems for new users who are used to the
access-anything style of DOS/Windows. This is a short guide aimed
at such novice users that explains the basics and also the commands
that are used to manage and administer these permissions.“
“Linux is a proper multi-user environment. In a multi-user
environment, security of user and system data is very important.
Access should be given only to users who need to access the data.
Since Linux is essentially a server OS, good and efficient file
security is built right into Linux. Of course, such security does
create problems for users, especially novice users. Many user
queries are due to incorrect file permissions or just because a
user ignores that fact that the file permissions do not allow
access. “
“First, let’s check out the file permissions. File permissions
are defined for users, groups and others. User would be the
username that you are logging in as. Further more, users can be
organized into groups for better administration and control. Each
user will belong to at least one default group. Others includes
anyone the above categories exclude.”