IT 244: Introduction to Linux/Unix - Class 8 Exercise, Thursday, February 20th

IT 244: Introduction to Linux/Unix
Class 8 Exercise, Thursday, February 20th

Log in to users

Run the ssh client

Use the values in the table below to connect to users.

ssh configuration parameter	value
protocol	ssh
ssh version	2
ssh port	22
host	users.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 ex08 directory
```
    mkdir  ex08
```
Go to your ex08 directory
```
    cd  ex08
```

file

Return to your home directory
```
    cd
```
Run file on the contents of your home directory
```
    file * 
```

Look at the files in my it244_files directory

    file /home/ckelly/course_files/it244_files/*

Pipes

Make sure you are in your home directory
```
    cd
```
Go to your ex08 directory
```
    cd it244/ex/ex08
```
Make sure you are in your ex08 directory
```
    pwd
```
Copy red_sox.txt to your home directory
```
    cp  /home/ckelly/course_files/it244_files/red_sox.txt  .
```
Make sure you include the dot, . , or you will get an error message.
Make sure the copy operation worked
```
    ls
```
Find all Red Sox wins
```
    grep Win red_sox.txt 
```
Find all Red Sox wins at home
```
    grep Win red_sox.txt | grep vs
```
Here, the first instance of grep is the source, and the second is a filter.
Find all Red Sox wins at home, sorted in reverse order by date
```
    grep Win red_sox.txt | grep vs | sort -nr
```
This is a pipeline, with three separate processes, one for each command.

date

Show today's date
```
    date
```
Use the formatting options of date to show today's date using the format YYYY-MM_DD
```
    date +"%Y-%m-%d"
```

which

Find the executable file for the Python interpreter
```
    which python
```
Find the executable file for tar
```
    which tar
```

whereis

Find files associated with python
```
    whereis python
```
Note that whereis reveals many more files.
Find files associated with tar
```
    whereis tar
```

locate

Find all files with "foot" in their name
```
    locate foot
```

who

Find out who else is logged in to users
```
    who
```
Look at the details of your current session
```
    who am i
```

finger

Use finger to see who else is connected to your current host
```
    finger
```
Use finger on your own Unix username
```
    finger YOUR_UNIX_USERNAME
```
In place of YOUR_UNIX_USERNAME, you must put your Unix username.
Run finger on the first name "Chris"
```
    finger Chris
```

Filename Extensions

Create the text file foo.txt with a text editor
```
    nano foo.txt
```
Add some text

Save and quit.
Run cat on the file
```
    cat foo.txt
```
cat prints the file to the terminal.
Change the extension of foo.txt
```
    mv foo.txt foo.xyz
```
Open the renamed file with nano
```
    nano foo.xyz
```
nano opens the file without difficulty.

nano does not care about the extension.
Change some text in the renamed file

Save and quit.
Run cat on the renamed file
```
    cat foo.xyz
```
cat does not care about the extension.

The Hierarchical Filesystem

Find your current location
```
    pwd
```
You should be in the ex08 directory inside your ex directory of your it244 directory.
Go up one level to your parent directory
```
    cd ..
```
.. means the directory one level up.
Look at your current location
```
    pwd
```
You have moved up one level.
Go to the root directory
```
    cd /
```
Look at your current location
```
    pwd
```
You are at the top of the filesystem.
Look at the directories inside the root directory
```
    ls
```
Notice that the home and courses directories are subdirectories of the root directory.
Return to your home directory
```
    cd
```
Look at your current location
```
    pwd
```
Your home directory is inside the directory named home, which is, itself, under the root directory, /.
Return to the ex08 directory inside your it244/ex directory
```
    cd it244/ex/ex08
```
Check you current location
```
    pwd
```

Filenames

Run stat to get some information about the Linux host
```
    stat -f /home
```
Run stat with grep to learn the largest filename possible
```
    stat -f /home | grep Namelen
```
Create a file with spaces in the name
```
    touch 'hello there'
```
If you did not put "hello there" in quotes, you would create 2 files, hello and there.
List the contents of your current directory
```
    ls
```
It looks like you have created two files.
Perform a long listing on your current directory
```
    ls -l
```
Now you can see that there is only one file.
Remove the file you just created
```
    rm 'hello there'
```
Make sure the file is gone
```
    ls 
```

Case Sensitivity

Create the file foo.txt
```
    touch foo.txt
```
Look at the contents of the directory
```
    ls
```
Create another foo.txt file
```
    touch foo.txt
```
Look at the contents of the directory
```
    ls
```
You only have one foo.txt file since you can only have one file with a given name in any one directory.
Create the file Foo.txt
```
    touch Foo.txt
```
List the files in your current directory
```
    ls
```
You have two files since, as far as Unix is concerned, foo.txt and Foo.txt are totally different file names.
Create some new files
```
    touch fOO.txt FOO.txt FOO.TXT
```
List the contents of your current directory
```
    ls
```
You should see the files you just created since they have different capitalizations.
Remove all .txt files from your ex08 directory
```
    rm  *.txt
```

Bash Script for this Exercise

Go to your ex08 directory
```
    cd ~/it244/ex/ex08
```
Make sure you are in you ex08 directory
```
    pwd
```
Create the script ex08.sh
```
    nano  ex08.sh
```
Add the following line, and then skip two empty lines:
```
    # Exercise 8, First Portion
```
Write into this file all the commands from the sections above

Copy all the commands from the sections file to finger.

Do not call nano inside your script.
Skip two empty lines, add the following line, and then skip two more empty lines:
```
    # Exercise 8, Second Portion
```
Write into this file commands from the indicated sections above

Copy all the commands from the sections The hierarchical filesystem to Case sensitivity Skip the section Filename extensions.
Save this file

Save and quit.
Test the script
```
    bash  ex08.sh
```
Fix any errors you find.

If you have trouble, see me.

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 8 Exercise, Thursday, February 20th