1. The Unix File sytem

2. Introduction Tree structure …

3. The on-line manual man gives detailed information about UNIX commands and other facilities Details include command format, description, examples, known problems, related files and commands Sections for commands, programming, admin and others man intro for the introduction man man (of course)

4. UNIX Filestore Files and directories The filesystem hierarchy File handling commands

5. Files From the user’s point of view, all information on the computer is stored in files Files may contain many kinds of information, including programs, data and documents Like paper files, they have a name (chosen by the user) and some content By convention, the filename suffix suggests the type of content

6. Example files Me.sh = Shell script Me.pl = Perl script Me.txt = Text file Me.jpg, Me.png, Me.gif = Image files Me.html = HTML web page file Me.zip, Me.gz Me.bz2 = Compressed file Me.tar = Archived file Me.log = Log file These are just conventions and are not enforced by the operating system!

7. Directories Files are stored in directories (folders in Windows) Each directory may contain many files and also other directories By convention, directory names do not usually have suffixes

8. The filestore There is a single hierarchical filestore that is shared by all users It might be spread over the network, may involve many disks on may different computers and may even be linked to other filestores

9. Each user has their own personal home directory (~) There are also common areas for programs, administration, etc. The filestore starts at the root directory (/) A user is always in a current working directory (CWP) from which they give commands to access files When users log on, the CWP is set to their home directory The filestore

10. (root) staffusrbinstudetc ResearchTeachingPrivate pgugitmasters xxxgtrxxx CUA Coursework1.txt CUA xxx02uxxx04u MVR Lecture1.ppt Lecture2.doc.profile The filestore

11. Where am I in the File Structure? pwd prints the pathname of the current working directory cd pathname changes current directory –with no argument it goes to the home directory

12. Where am I in the File Structure? (2) robin$ pwd /stud/ug/xxx04u robin$ cd UST robin$ pwd /stud/ug/xxx04u/UST robin$ pwd /stud/ug/xxx04u/UST robin$ cd.. robin$ pwd /stud/ug/xxx04u/ (root) staffusrbinstudetc ResearchTeachingPrivate pgugitmasters xxxgtrxxx CUA Coursework1.txt UST xxx02uxxx04u MVR Lecture1.ppt Lecture2.doc.profile

13. File handling commands – Viewing File Contents The cat [filename…] command displays the contents of the named files It reads the contents of the file(s) and outputs to the shell window with no arguments cat simply echoes back what you type at the keyboard there is no scrolling with the cat command more [filename…] lets you scroll through a file –also less [filename…]

14. Viewing File Contents (2) head displays the first 10 lines of a file tail displays the last 10 lines of a file

15. ls [pathname…] lists the contents of the named directories –with no argument, the current directory is listed mv pathname1 pathname2 moves a file from pathname1 to pathname2 –if pathname2 already exists, then its previous contents are lost –if not, then it is created Viewing and Changing Directory Contents

16. cp pathname1 pathname2 copies the contents of pathname1 to pathname2 –if pathname2 already exists, –then its previous contents are lost –if not, then it is created rm pathname removes files but not directories (be careful) Viewing and Changing Directory Contents (2)

17. mkdir pathname... creates a new directory –it fails if they already exist Manipulating Directories robin$ rmdir fred rmdir: directory “fred”: Directory not empty robin$ mkdir fred mkdir: failed to make directory “fred”; File exists rmdir pathname removes directories –it fails if they are not empty