Software Development Degree BTO120 Lecture Notes - Lecture 4: .Tz, Tape Drive, Bzip2
31 Oct 2016
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Permissions can only be changed by file owner or superuser (system administrator) Chmod is used to alter access permissions to an existing file or directory. The 9 permission bits displayed in an ls -al listing are read/write/execute for. Xxx is 3 octal digits representing the binary string rwxrwxrwx where the first three characters are read/write/execute permission for the user, the next three for the user"s group, and the last three for all others. Eg. chmod 640 file1 - would give the user read and write permission, everyone in his group would have read permission, and all others would have no permission. This is called the octal or absolute method of changing permissions. Chmod u+r filename whatever he had before. U represents user, could also be g for group, o for other, a for all. + represents addition of permission, could also be - for removal, = for set.
