We will use LINUX on the TS111 lab systems. The purpose of this lab is to become familiar with the basics of the UNIX shell.

The basics of how to access LINUX are described here.

1. Check your current directory with the pwd command.

2. Check to see what is in your current directory with the "ls -l" command.

3. In order to be sure there are some files, do this:
   • Map network drives using "mnet logon student userid".

   • Copy a set of files: cp tdrive/erodd/files304/* . Note: The "." (period) is important! It means to the current directory.

     Note: The "*" means copy every file in the tdrive/erodd/files304 directory.

4. See what is in your directory with "ls" and then "ls -l" and then "ls -ld" and then "ls -la".
   What can you see about the length of filenames?

5. Do a

   df

   command. This shows the currently mounted filesystems. Which filesystem has all the space? Is your current directory on this filesystem?

6. Use the "cat" command to display the file /etc/inittab
   This file is the list of things started with UNIX is booted.

7. Use "cat" to list a file which does not exist.
   Now redirect output from cat with "cat xxxx > soiii" (iii is your initials so you don't conflict with other students). Use "ls -l" to see how large "soiii" is.
   Do you still see the error? Now redirect standard error with:

   cat xxxx 2> seiii

   What do you see? How large is "seiii"? What is in "seiii"?

8. Now create a file using "echo". First try

   echo my data

   to see that echo simply writes to standard out. Use redirection of standard out

   echo my data > fiii

   to create a file named fiii. Now use the "ls" command to make sure you created the file. Now erase this file with

   rm fiii

9. Use "cat" to see what is in the files "ss1" and "ss2". Now sort one of these files with: "sort < ss1".
   Now use "cat" to display them both at one time.

10. Now we can pipe the output of cat into sort to sort both files together!

11. Try grep: For example, try:

    grep A ss*

    This will show all lines in files starting with "ss" which have the string "A" in them.

12. grep is a very powerfull command! We are using only its most basic function! Two simple options are:

    grep -r string *  # Search all files in the current directory, and
                      # all its subdirectories (-4) for "string"
    
    grep -l string *  # Search all files in the current directory for "string",
                      # but display just the filenames, not the lines
                      # containing the string.
    
    grep "This Day" * # Notice the quotes. If a search string has blanks, or
                      # other special characters, it must be enclosed in ""
    
    Another important shell command not in the book is "find" which
    is like DOS dir with the "/s" option. "find" has other advanced options
    such as executing a command using each file found as an argument.
    
    We will use a command not in the book: find. It was
    designed when the ls command did not have an option to recurse
    subdirectories. Still, find has useful function like finding files
    with a modification date less (or more) than so many days old.
    Also, find can execute a command against each file found.
    Try the command: 
    find /usr/local -name "sw*" 
     which will
    display all files in the /usr/local directory and its subdirectories which
    start with the letter "sw".
    To search the entire system for a file, the command is:
     
    find / -name "somefile"
    
    Two warnings:
    
    Do not use a find of the whole system while logged on with
    mnet. This will search the whole tdrive which takes a long time!
    Many directories deny permissions to your userid and will produce
    a LOT of error messages. To avoid them, redirect error output to
    the special device /dev/null:
    
    find / -name "somefile" 2> /dev/null
    
    
    Try using sort with STDIN input (i.e. the keyboard). Just type "sort"
    with no parameters. You can then type lines to be sorted. Terminate the
    input with Ctrl-d and sort will write a sorted list to standard out (the
    screen).
    
    Try using sort using redirection. Create a file using "vi" and
    then sort it. For example, to sort file "/tmp/abc",
    sort < /tmp/abc
    
    will put the sorted output to the console (STDOUT).
    To put the sorted output to a file, redirect the output. For example:
    sort < /tmp/abc > /tmp/sortedfile
    
    Do a command with lots of output. You can try
    ls -l /usr/bin
    
    Now use the more command:
    ls -l /usr/bin | more
    
    LINUX has a more powerful processor 
    called less
    ls -l /usr/bin | less
    
    The less command accepts normal vi
    editor commands including  PgUp and PgDn keys and the search
    command (/string). To quit, type :q and press ENTER.
    
    Examine all the "environment" variables available to your userid:
    env
    
    Use echo to display an environment variable. We will display $PATH.
    echo $PATH
    
    Note: In Windows, display an environment variable with:
    echo %PATH%
    
    Create your own environment variable. Pick your own name __________
    
    Set the variable.
    your-name=value
    
    Note that there CANNOT be blanks around the '=' sign!!
    Now display your variable:
    echo $your-name
    
    
    Remember, that names are case sensitive!
    
    In a later lab, we will see that programs can access these
    environment variables.
    

To Turn in

Nothing. There is no grade on this lab. You will, however, be responsible to understand this lab on quizzes and exams.