Permissions specify what a particular person may or may not do with respect to a file or directory. As such, permissions are important in creating a secure environment.
There are two permissions, one for reading and one for writing, and they are managed independently. This is not a bug since the documented behavior coincides with the actual behavior and there is no good reason to require a different behavior.
Having write permissions without read permissions doesn't make much sense for regular files. It does make sense for various special files. Some systems allow append-only files.
This is useful for log files, for example. It can make sense to allow many users to create log entries, but not to allow them to erase or overwrite existing entries hence: A program may be allowed to write to a named pipe without being allowed to read from it.
Some devices are write-only. For example, a sound output device connected to a loudspeaker but no microphone should have write permission but no read permission. There are various special filesystems where reading or writing to a file has an immediate effect instead of retrieving or adding data to storage.
If that command doesn't provide any feedback, the special file is made write-only.The main reason to allow write access without read access is that it simplifies the management of permissions, both inside the kernel and in user programs. There are two permissions, one for reading and one for writing, and they are managed independently.
If you want to change urbanagricultureinitiative.com so those in your group do not have write access, but can still read the file, remove the access by subtracting two (2) from that set of numbers.
The numerical values then become six, four, and four (). Jun 25, · Linux can establish different types of groups for file access.
In a one home computer environment anyone who uses the computer can read this file but cannot write to (modify) it. This is a completely normal situation. Linux, like other operating systems, organizes itself using directories and files that can potentially be accessed, altered, or executed.
To prevent internal anarchy, Linux gives different levels of permission for interacting with those files and directories. If you want to modify those permissions, the chmod (change mode) command is what you need.
Changing file permissions¶ Linux for Programmers and Users, Section A file has three types of permissions (read, write and execute) and three sets of users (user (owner), group and other (world)) with specific permissions.
To best share with multiple users who should be able to write in /var/www, it should be assigned a common group. For example the default group for web content on Ubuntu and Debian is www-data. Make sure all the users who need write access to /var/www are in this group.