Minutes of the KLUG meeting, 26 October 1999

["Robert G. Brown" <bob@xxxxxxx>]

About 14 people were present when the meeting got started at 7:14 PM


Announcements: Bob Brown

[1] Michigan Polio Networks
    [A] Document Layout in progress
    [B] Publishing that soon (to the MPN group)
     - See Bob or Brenda Williams if you wish to volunteer.
       The web site we're building is about the after-effects of Polio
       and is itherwise a great opportunity to learn about HTML and web
       site construction.

[2] Community Outreach Project
    We are waiting for wod on times to complete filming this production at
    the studio. The local community TV system reaches 55,000 houselholds in
    the Kalamazoo area. Being visible there will help KLUG and Linux.

[3] Boogies Linux Workstation Project.
    [A] Configuration and selection of software is essentially completed.
    [B] Security Review, and deployment remain.

Speaker: Jamie McCarthy, on Linux File systems

[1] Linux file structure
   /  root diretory, also the "/" character is a separator.

    myfile is a relative specification... another example...

          somedir/myfile 
    is the position of "myfile" relative to the current working directory.

          /somedir/myfile
    is an absolute path to a file, regardless of the current working directory.
[2] directories are files
    [A] All of Linux
    [B] Many kinds of files

[3] df - shows all currently mounted partitions... example:
     $ df
     Filesystem         1024-blocks  Used Available Capacity Mounted on
     /dev/hda2            1018329  243148   722569     25%   /

{"$" indicates a command prompt, the prompt on you system may be different}

[4] pwd - print working directory

[5] cd - Change directory. can be relative or absolute.
 
     $ pwd
     /etc/rc.d
     $ cd ../sysconfig
           Relative change, ".." moves to the parent of the current
           directory.
     $ pwd
     /etc/sysconfig
     $ cd /usr/local/bin
     $ pwd
     /usr/local/bin

[6] ls - list files in directory
    [A]
     $ ls -l 
     -rw-r--r--   1 bob      users         35423 Dec  2  1998 contents
     drwxr-xr-x   4 bob      users          1024 May 22  1998 fonts
         ^        ^  ^         ^              ^     ^           ^
     permissions  #  owner    group    size (bytes) Creation    name
                 hard                               or update
                 links                                date

     (-l is "long", or detailed, listing)
     Many options to the ls command
     
     [B] ls -sF   s -file size F - shows type of file by suffixing a character.

       $ ls -sFls -sF
       total 477
       242 FreeAPL.zip     70 apl11src.tgz     1 fonts/
        88 apl11bin.tgz    36 contents        30 pricefilter*
        10 too

        fonts is a directory, pricefilter is executable
        The others are regular files.
     [C] ls -a  - show files that start with a "." character.
       $ ls -aF
        ./             ../            .bash_history  pix/

[7] cp  The copy command... make a copy of a file, or files.
     cp -a "copy all" [actually, copy "archive", preserve all the attributes
     of a file, including permissions, and any subdirectories]

[8] mv move file (or directory), even across file systems (unlike some UNIX
    systems).

[9] rm  - remove file -i = ask before rm -r remove recursively, -f = force, or
          no questions. rm -rf / = remove every file in the system!

[10] file  FILENAME - Tells what type of file FILENAME is.
    example:
    $ file FreeAPL.zip  
    FreeAPL.zip: Zip archive data, at least v2.0 to extract 

[11] umask PERMISSIONS - determines what permissions a file will have at
     file creation time. IN many cases this is set to 022. 002 was reccomended
     instead.
------------------------------------------------------------------------
FILE PERMISSIONS: Shown in ls -l above:
{vertical bars added for clarity, view with non-proportional font}
-rw-|r--|r--|
^ ^   ^    ^
| |   |    |
| |   |    |
| |   |    +--- All users
| |   +--- The group the owner belongs to.
| +----The owner
+----"d" here if the file is really a directory.

permissions can be: r - Read access
                    w - Write acccess
                    x - executable
                    s - executable as root
------------------------------------------------------------------------

12. su -  become "The superuser" (aka root).
       ^         DO NOT run as "rrot" longer than needed.
       |
       +---causes login scripts to execute, a GOOD idea.
    A # prompot (instead of $) indicates running as root.

13. # exit   to reutrun to the former user id ASAP.
    Running as the superuser overrides all ownership settings.

14. Adding filesystems....
    # mount /mnt/cdrom
      may be all it takes to make a CDROM accessale on your Linux system. The
      FULL command is:
      mount /dev/hdc /mnt/cdrom -t iso9660 -o ro
      We're assuming here that the CDROM device is the master IDE device on
      the second IDE channel. What controls how much of this command you
      must enter? The contents of the file /etc/fstab. The less specific
      that file is, the more must be specified in the mount command itself.

15. Directories normally found, and worth browsing to learn about Linux...
      /home user files    /proc    /bin
      /root               /etc     /lib
      /tmp                /usr     /boot
      /mnt                /sbin    /dev
      /var                /bin
   Each of these has a specific purpose and meaning (maybe another 
   presentation!)

Note the use of THREE different meaning for the term "root":

1. "Root" directory, or "/"
2. "root" user id, the superuser, user id 0
3. /root, the normal default home directory of the user root.

Notes taken by Ralph Deal, transcription supervised, with minor additions by
R. Brown.