IT 244: Introduction to Linux/Unix - Class 5 Exercise, Thursday, February 11th

IT 244: Introduction to Linux/Unix
Class 5 Exercise, Thursday, February 11th

When finished: Remember to check with instructor to make sure you are recorded as having completed the class exercise!

Log in to pe15

Run the ssh client

Use the values in the table below to connect to .

ssh configuration parameter	value
protocol	ssh
ssh version	2
ssh port	22
host	pe15.cs.umb.edu
user name	your Unix username
Authentication method	password

Enter your password
A dialog box will appear on the screen into which you must type the password for your Unix account.

Directory for this Exercise

Make sure you are in your home directory
```
    cd
```
Go to your it244 directory
```
    cd  it244
```
Go to your ex directory
```
    cd  ex
```
Create an ex05 directory
```
    mkdir  ex05
```
Go to your ex05 directory
```
    cd  ex05
```

Working with Pagers

Use cat on the exercise #05 page
```
    cat  /home/ckelly/public_html/teaching/common/exercises/linux/intro/exercise_05.html
```
Scroll back up in your terminal session to see the beginning of the file.

Use more on the same file

    more  /home/ckelly/public_html/teaching/common/exercises/linux/intro/exercise_05.html

Move down one screen
```
    Space
```
Look at the more help section
```
    h
```
Use the Enter key to moves down a few lines
```
    Enter
    Enter
    Enter
```
Move to the end of the file

Hit Space as many times as you need to.

You should reach the end of the file and exit more.

Use less on the same file

    less  /home/ckelly/public_html/teaching/common/exercises/linux/intro/exercise_05.html

Move to the end of the file

Hit Space until you reach the end of the file.

You see (END) but you are still in less.
Examine the help section
```
    h
```
Quit the help section
```
    q
```
Hitting q the first time only gets you out of the help section.
Quit less
```
    q
```
Hitting q the second time only gets you out of less.

Create a typescript File

Make sure you are in your ex05 directory
```
    pwd
```
If the result of running this command is not
```
    ~YOUR_UNIX_USERNAME/it244/ex/ex05
```
where YOUR_UNIX_USERNAME is the name you created for your Unix account, see me.
Run the script command
```
    script --flush
```
This will create a typescript file in your ex05 directory.

You must perform the remaining steps in this exercise while script is still running.

If you make a mistake, simply try again.

Do not exit the script session until you have finished all the steps in this exercise.

Filename Completion

Create the directory test
```
    mkdir  test
```
Move to the test directory
```
    cd  test
```

Create some files

    touch  foo  foobar  foobletch  bletch

Use filename complete to run ls on bletch
```
    ls  ble[Tab][Enter]
```
Use filename completion to see all files with "foo" in the name
```
    ls  foo[Tab][Tab]
```
After the first Tab, you should hear a beep. After the second, all files beginning with "foo" should be displayed.
Keep typing to run ls on foobletch
```
    bl[Tab][Enter]
```
As you supply more letters in the filename, the completion mechanism narrows down the possibilities.

Experimenting with echo

Run echo with a string argument
```
    echo  foo  bar  bletch
```
Run echo using the -n option
```
    echo  -n  foo  bar  bletch
```
Notice that "foo bar bletch" appears before the normal prompt.

That is because the -n option turned off sending a newline character to advance to the next line.
Use echo to display a system variable
```
    echo  SHELL:  $SHELL
```
You must use a $ when displaying the value of a variable
```
    echo SHELL:  SHELL
```

hostname

Determine the name of your current host
```
    hostname
```
Determine the IP address of your current host
```
    hostname  -i
```

grep

Go to the it244_files directory

    cd   /home/ckelly/course_files/it244_files

Look at the contents of foo.txt
```
    cat  foo.txt
```
Look for lines with the string "foo" in foo.txt
```
    grep  foo  foo.txt
```
Experiment with the -i option

First look for "bar" without the -i option
```
    grep  bar  foo.txt
```
Now try the same search with -i
```
    grep  -i  bar  foo.txt
```
Use grep with the -r option

grep, when used with the -r option, looks in all subdirectories of the directory given to it as its second argument
```
    grep  -r  foo  .
```
The . means the current directory.

Everything up to the colon, : , is the path to the file in which the string was found.

The text after the colon is the line itself.

The entries in the directory .svn are associated with the versioning software, subversion, I use in all my work.
Use grep -v to remove unwanted lines

Many of the lines returned in the previous invocation of grep come from files with the string "svn" in their file names.

These are files created by subversion.

Let's remove these lines grep twice, using a pipe, |, to feed the output of the first invocation of grep into the input of the second
```
    grep  -r  foo  .  |  grep  -v  svn
```
Notice that all the entries in the subversion files have been removed.

We'll discuss pipes in a future class.

head

Display the contents of red_sox.txt
```
    cat  red_sox.txt
```
Display the first 10 lines of red_sox.txt
```
    head  red_sox.txt
```
Display the first line of red_sox.txt
```
    head  -1  red_sox.txt
```

tail

Display the last 10 lines of red_sox.txt
```
    tail  red_sox.txt
```
Display the last two lines of red_sox.txt
```
    tail  -2 red_sox.txt
```

sort

Look at fruit.txt
```
    cat  fruit.txt
```
Run sort on this file
```
    sort  fruit.txt
```
Sort this file in reverse alphabetical order
```
    sort  -r  fruit.txt
```
Look at numbers1.txt
```
    cat  numbers1.txt
```
Run sort on this file without any options
```
    sort  numbers1.txt
```
Since the numbers from 10 to 19 begin with a 1 they appear before 2
Sort numbers1.txt in numerical order
```
    sort  -n  numbers1.txt
```
Sort numbers1.txt in reverse numerical order
```
    sort  -nr  numbers1.txt
```
Note that sort allows you to combine options after the dash.

diff

Examine the contents of numbers1.txt and numbers2.txt
```
    cat  numbers1.txt
    cat  numbers2.txt
```
Use diff to compare numbers1.txt and numbers2.txt
```
    diff  numbers1.txt  numbers2.txt
```
The output is hard to read, because it contains instructions for the Unix patch utility to convert the first file given at the command line to the second.
Use the -y option to diff to create readable output
```
    diff  -y  numbers1.txt  numbers2.txt
```
This output is much easier to read.

End your script Session

Exit from your script session
```
    exit
```
You need to do this or the typescript file will never be created
Look at the contents of the typescript file
```
    cat  typescript
```

Create a Bash script

Go to your home directory
```
    cd
```
Go to your it244 directory
```
    cd  it244
```
Go to your ex directory
```
    cd  ex
```
Go to your ex05 directory
```
    cd  ex05
```
Create the script file ex05.sh
```
    nano  ex05.sh
```
Write into this file commands from certain of the sections above

Go back to the section of this Class Exercise called Experimenting with echo.

Enter all the commands from the echo section to the section called diff into this script file.

Do not run the more or less commands inside ex05.sh

Do not use Tab completion inside ex05.sh

You do not have to use echo in scripts for the Class Exercise.
Save and quit
Run this script
```
    bash  ex05.sh
```

When finished:

Remember to check with instructor to make sure you are recorded as having completed the class exercise.
When you are ready, be prepared to show me:
- Your command line interaction -- in other words, scrolling up in the terminal windows, not just running the history command!
- Any other deliverables specified in the instructions, such as scripts or other files.

IT 244: Introduction to Linux/Unix Class 5 Exercise, Thursday, February 11th