chmod Basics

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chmod = change file modes

PermissionsOwnerGroupOthers
chmod 777 rwxrwxrwx
chmod 666 rw-rw-rw-
chmod 555 r-xr-xr-x
chmod 444 r--r--r--
chmod 333 -wx-wx-wx
chmod 222 -w--w--w-
chmod 111 --x--x--x
chmod 000 ---------

After chmoding a file you can use ls -l to view the permissions.

Using the above chart you can combine permissions.
chmod 644 = rw-r--r--
chmod 731 = rwx-wx--x

Owner = user that created the file
Group = users in the same group as owner
Others = the rest of the users on the system

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