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File Systems

File Systems. Sources and Resources: A Students Guide to UNIX, by Hahn Paula Davidson’s Handout on UNIX. Internet Applications: telnet For Remote Login. telnet remote_host_name Internet application Used to login to a remote computer

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File Systems

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  1. File Systems Sources and Resources: A Students Guide to UNIX, by Hahn Paula Davidson’s Handout on UNIX

  2. Internet Applications:telnet For Remote Login • telnet remote_host_name • Internet application • Used to login to a remote computer • Allows your expensive PC to look like a dumb glass tty or asynchronous terminal • At UNCA, you will use telnet to login to the servers: • bulldog.unca.edu • candler.cs.unca.edu or busbee.cs.unca.edu

  3. Internet Applications:ftp For Moving Files • ftp remote_host_name • Internet application • Used to move files to or get files from a remote computer • At UNCA, you will use ftp to move files to and from the servers • bulldog.unca.edu • candler.cs.unca.edu or busbee.cs.unca.edu

  4. UNIX File System • Hierarchical • Contains files • Text files • Special files • Standard I/O – Keyboard, Display • Device files • Directories

  5. File Structure - Hierarchical

  6. Paths • Relative newDirectory newDirectory/myFiles/homework1.doc • Absolute /HOMEDIR/faculty/bruce/newDirectory /HOMEDIR/faculty/bruce/newDirectory/myFiles/homework1.doc • What directory are you in? The command: pwd

  7. Commands mkdir • Make a directory • mkdir newDirectory • Makes a new directory named newDirectory as a child of the current directory

  8. Commands rmdir • Remove a directory • rmdir newDirectory • Removes a directory named newDirectory. • If specified as a relative path (not beginning with a /) the directory to be removed must be in the current working directory.

  9. Commands ls • List contents of a directory • ls newDirectory • Lists the contents of newDirectory • ls • Lists the contents of the current working directory • ls –a • Lists all the contents of the current working directory, even the hidden files

  10. Commands ls • List contents of a directory • ls –l • Lists all the contents of the current working directory in a long listing which displays the file permissions as well as the owner, group, size in bytes, modification date

  11. Commands cd • Change directory • cd // sets current working directory // to your home directory • cd otherDirectory // sets current working directory // to otherDirectory

  12. Commands cd • Change directory • cd.. // sets current working directory // to the parent directory or moves // one level up the hierarchy • cd ../.. // sets current working directory // to 2 levels up the hierarchy

  13. Commands mv • Move or rename a file mvfile1.txt file1.html // renames file1.txt to file1.html mvfile1.txt newDirectory/file1.html // moves file1.txt to newDirectory/file1.html

  14. To do • telnet into your account using SSH • List the contents of your home directory. What directories exist in your home directory? • Change directories into your public_html directory. • Change back to your home directory. • Change to the root directory.

  15. To do • Change to the root directory. • Change back to your home directory. • Create a subdirectory called junk • Change into junk and create two subdirectories: j1 and j2. • Remove j1, j2 and junk.

  16. File Permissions • The various flavors of UNIX including LINUX and OS/X store permissions for every file. • There are three independent permissions • Read • Write • Execute • You can change permissions for your files.

  17. File Permissions for Directories • The various flavors of UNIX including LINUX and OS/X store permissions for every directory. • There are three independent permissions • Read - read names in a directory • Write - make changes (create, move, copy, remove) • Execute - search the directory (cd into it) • You can change permissions for your directories.

  18. Permissions: an octal representationchmod permissionsfile • Read: 4 100 • Read + Write: 6 110 • Read + Execute: 5 101 • Read + Write + Execute: 7 111 • Write: 2 010 • Write + Execute: 3 011 • Execute: 1 001

  19. chmod permissionsfile • Each file has three sets of permissions • Permission modes exist for you your_group world rwx rwx rwx • chmod 777 myWideOpenFile • chmod 744 myOtherFile • chmod 700 mySecretFile

  20. Displaying File Permissions • ls -l -rw-r--r-- 1 mmasuser staff 20788 15 Dec 14:14 Adobe SVG 3.0 Installer Log drwx------ 19 mmasuser staff 646 21 Jan 14:53 Desktop drwx------ 21 mmasuser staff 714 16 Jan 15:13 Documents drwx------ 29 mmasuser staff 986 11 Nov 14:09 Library drwx------ 17 mmasuser staff 578 27 Nov 19:55 Movies drwx------ 4 mmasuser staff 136 9 Oct 13:52 Music drwx------ 5 mmasuser staff 170 19 Dec 19:27 Pictures drwxr-xr-x 4 mmasuser staff 136 9 Oct 13:30 Public drwxr-xr-x 5 mmasuser staff 170 9 Oct 13:30 Sites

  21. In class • What are the file permissions forpublic_html? • Change directories into your public_html directory. Create a new directory named 179. • Create 3 subdirectories of 179: project1, project2, and homework.

  22. In class • Move index.html,your style file, and any other files referenced by index.html into your 179 directory. • Go to the student work page linked from the class syllabus. Make sure the link to your class page works!

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