In UNIX and Linux, file permissions are defined by three sets of permissions for three types of users: the owner, the group, and others. These permissions are read (r), write (w), and execute (x). In addition to these basic permissions, there is a special type of file permission called setuid (short for “set user ID”).<\/p>\n
When setuid is set on an executable file, the file will be executed with the privileges of the file’s owner instead of the privileges of the user who runs the file. In other words, when you run an executable file with setuid set on it, you temporarily become the owner of the file and gain the same permissions as the owner.<\/p>\n