home | O'Reilly's CD bookshelfs | FreeBSD | Linux | Cisco | Cisco Exam  


UNIX Power Tools

UNIX Power ToolsSearch this book
Previous: 22.3 Who Will Own a New File? Chapter 22
File Security, Ownership, and Sharing
Next: 22.5 Group Permissions in a Directory with the setgid Bit
 

22.4 Setting an Exact umask

You can use the umask command to set the default mode for newly created files. Its argument is a three-digit numeric mode that represents the access to be inhibited  - masked out - when a file is created. Thus, the value it wants is the octal complement of the numeric file mode you want. To determine this, you simply figure out the numeric equivalent (1.23 ) for the file mode you want and then subtract it from 777. For example, to get the mode 751 by default, compute 777-751 = 026; this is the value you give to umask :

% umask 026

Once this command is executed, all future files created will be given this protection automatically. System administrators can put a umask command in the system initialization file to set a default for all users. You can set your own umask in your shell setup files (2.1 ) . Article 22.2 has more information about the umask and two aliases for changing yours.

- AF from O'Reilly & Associates' Essential System Administration , Chapter 2


Previous: 22.3 Who Will Own a New File? UNIX Power Tools Next: 22.5 Group Permissions in a Directory with the setgid Bit
22.3 Who Will Own a New File? Book Index 22.5 Group Permissions in a Directory with the setgid Bit

The UNIX CD Bookshelf NavigationThe UNIX CD BookshelfUNIX Power ToolsUNIX in a NutshellLearning the vi Editorsed & awkLearning the Korn ShellLearning the UNIX Operating System