UNIX permissions cheat sheet

Permissions of 644 mean that the owner of the file has read and write access, while the group members and other users on the system only have read access . For executable files, the equivalent settings would be 700 and 755 which correspond to 600 and 644 except with execution permission.

Nine characters denotes the three types of permissions.

755 – owner can read/write/execute, group/others can read/execute . 644 – owner can read/write, group/others can read only.

755 means read and execute access for everyone and also write access for the owner of the file . When you perform chmod 755 filename command you allow everyone to read and execute the file, the owner is allowed to write to the file as well.