Unix Operating System

1. Unix Operating System The UNIX file system (2) อ้างอิงจาก http://apollo.lsc.vsc.edu Computer Science Department (FLAS-KU) - Prasertsak U.

2. Unix File System Organization • Every Unix has a similar organization of the file system. A listing of the root directory ("/")  Computer Science Department (FLAS-KU) - Prasertsak U.

3. Unix File System Organization bin - contains system binary executables boot - contains files necessary for the system to boot up dev - contains device files which function as an interface to the various hardware drivers. These will vary greatly depending on the version of Unix. etc - contains system configuration settings home - contains the user's home directories lib - contains system libraries mnt - used to hold mount point directories for removable storage proc - contains a virtual file system which holds information about running processes and the state of the system. Computer Science Department (FLAS-KU) - Prasertsak U.

4. Unix File System Organization sbin - contains static binary executables needed for the system tmp - temporary directory used by many applications usr - contains binaries, data and settings for various applications. The structure of /usr mimics the root file system organization. var - stores logs, data for services and other transient data. Computer Science Department (FLAS-KU) - Prasertsak U.

5. Unix File System Organization • Your Home Directory. The home directory is unique for each user account on the system. This directory can be managed completely by the user and will not be accessible to other users. The home directory can be referenced by the "~" character. Computer Science Department (FLAS-KU) - Prasertsak U.

6. Unix File System Organization • Symbolic Links. Symbolic links are part of the Unix file system. A pointer to another file or directory on the file system. Symbolic links have not permissions of their own. The target file or directory permissions will determine the access privileges. Computer Science Department (FLAS-KU) - Prasertsak U.

7. Unix File System Organization • Symbolic Links. Symbolic links are created with the ln command with the "-s" option: รายละเอียดของ hello.cจะเหมือนกับ tt.cเนื่องจากเป็นข้อมูลที่เดียวกัน Computer Science Department (FLAS-KU) - Prasertsak U.

8. Unix File System Organization • Hidden File. In Unix files whose names begin with the dot character, ".", are considered hidden. Most commands will not display these files by default. Thels command with the "-a" option will display all hidden files. Computer Science Department (FLAS-KU) - Prasertsak U.

9. Unix File System Organization • The "." and ".." Directories Two special hidden directories listed within each directory are named "." and "..“ • The "." directory refers to the working directory. • The ".." directory always refers to the directory above the working directory. Computer Science Department (FLAS-KU) - Prasertsak U.

10. Unix File System • Sample organized Computer Science Department (FLAS-KU) - Prasertsak U.

11. Unix File System Organization • The df Command. The df command is used to report how much of the file systems are in use. Computer Science Department (FLAS-KU) - Prasertsak U.

12. Unix File System Organization • The “mount" and “umount" Commands mount will "attach", or mount, the device to a directory on the file system. This directory is called the "mount point" and must exist before attempting to mount a file system. Typically only the super-user has the ability to mount file systems. Computer Science Department (FLAS-KU) - Prasertsak U.

13. Unix File System Organization • The “mount" and “umount" Commands To remove a mounted file system the umount command Computer Science Department (FLAS-KU) - Prasertsak U.

14. Unix File System Organization • Some hosts have the system configured so that a user can mount certain file systems as defined by the file /etc/fstab Computer Science Department (FLAS-KU) - Prasertsak U.