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Tutorial 2 - Unix / Linux File Management

20,314 bytes added, 17:38, 30 August 2021

→‎INVESTIGATION 2: MANAGING TEXT FILES

= INVESTIGATION 2: MANAGING TEXT FILES =

<table align="right"><tr valign="top"><td>[[Image:nano-text-editor-1.png|thumb|right|250px|The '''Nano Text Editor''' is Easy to Operate for Novice Users.]]</td><td>[[Image:vi-text-editor-1.png|thumb|right|300px|The '''vi Text Editor''', although taking longer to master, has outstanding features and allow the user to be more productive with editing text files.]]</td></tr></table>

Since IT students will be working in the Unix / Linux command line environment, it is useful to learn a least two common command-line '''text editors'''.

Although '''programming students''' can use '''graphical IDE's''' to code and compile programs, they can '''create source code''' using a text editor and '''compile their source code''' in the '''Matrix''' server to generate executable programs (without having to transfer them for compilation or execution).

'''Networking and Tech Support students''' can use a text editor to '''edit configuration files'''. These students in upper grades will become familiar with the process of installing, configuring, and running network services and text editors are an important tools to help setup but also "tweak" or make '''periodic changes in networking services configuration'''.

The two most readily-available command line text editors in Linux are '''Nano''' and '''vi'''. The Nano text editor would seem like an easier-to-use text editor, but vi (although taking longer to learn) has outstanding features and allow the user to be more productive with editing text files.

===Part 1: Creating Text Files Using The Nano Text Editor===

You will now learn basic editing skills using the '''Nano''' text editor including '''creating''', '''editing''', and '''saving''' text files.

'''Perform the Following Steps:'''

# Make certain that you are located in your home directory. [[Image:directory-structure-10.png|right|150px|thumb|]]

# '''Create''' the following directory structure (displayed on the right side) by issuing a '''single Linux command''' (You should know how to do this from the previous INVESTIGATION).

# Issue a Linux command to check that you correctly created those directories.

# Issue the following Linux command to edit a text file called '''mytext.txt''' in the '''linux/practice''' directory: nano textedit/practice/mytext.txt '''NOTE:''' When using the '''Nano''' text editor, you are placed in '''INPUT''' mode, so you can enter text immediately. [[Image:nano-text-editor-2.png|right|400px|thumb|Enter the following text that appears in this diagram.]]

# Enter the lines shown in the other diagram of the nano text editor on the right side. '''NOTE:''' Refer to the table below for a list of common '''Nano''' navigation & editing commands: <table cellpadding="5"><tr><th style="border-bottom: 1px solid black;">Key(s)</th><th style="border-bottom: 1px solid black;">Purpose</th></tr><tr valign="top"><td style="font-family:courier">'''<ctrl><SPACEBAR>''', '''<esc><6>'''</td><td>Move forward/backward one word</td></tr><tr valign="top"><td style="font-family:courier">'''<ctrl><a>''', '''<ctrl><e>'''</td><td>Move to beginning/end of line</td></tr><tr><td style="font-family:courier">'''<ctrl><k>'''</td><td>Cut line</td></tr><tr><td style="font-family:courier">'''<esc>6'''</td><td>Copy Line</td></tr><tr><td style="font-family:courier">'''<ctrl>'''</td><td>Paste Cut/Copied Text</td></tr><tr><td style="font-family:courier">'''<ctrl><g>'''</td><td>Display help screen (ctrl-x to exit help screen)</td></tr><tr><td style="font-family:courier">'''<ctrl><x>'''</td><td>Save editing changes and exit</td></tr></table>

# Referring to the table above, practice navigating and editing your entered lines for practice.

# To '''save''' your editing session, press: <ctrl>x

# You will be prompted to modify your file: type the letter y for '''yes'''.

# The name of the file will be displayed, Press ENTER.to save editing changes for that file name. '''NOTE:''' This prompt for file name allows you to change the name of the file if you wish. By pressing '''ENTER''', it will accept the default filename.

# Perform some more editing operations based on the editing chart above.

# '''Save''' your editing session and '''exit''' your text editor.

===Part 2: Creating Text Files Using The vi Text Editor===

[[Image:vi-screen.png|right|300px|thumb|Using the '''vi''' text editor.]]

You will now learn basic editing skills using the '''vi''' ('''vim''') text editor including '''creating''', '''editing''', and '''saving''' text files.

The '''vi''' ('''vim''') text editor (although taking longer to learn) has outstanding features to increase coding productivity.

The major different between nano and vi is that '''vi starts in COMMAND LINE mode'''. You need to issue letter commands to enter text. Also you can press colon “: ” in COMMAND mode to enter more complex commands.

'''Perform the Following Steps:'''

# Make certain that you are located in your home directory.

# Issue the following Linux command to edit a text file called '''othertext.txt''' in the '''linux/practice''' directory: vi textedit/practice/othertext.txt '''NOTE:''' When using the '''vi''' text editor, you are placed in '''COMMAND''' mode, so you need to issue a command to switch to ''INPUT'' mode. [[Image:vi-text-editor-a.png|right|200px|thumb|Enter the following text that appears in this diagram.]]

# Type the following key to enter ''INPUT'' mode: i You should notice you are in ''INSERT'' mode by seeing the notification '''-- INSERT --''' at the bottom left-hand side of the application screen.

# Enter the line shown in the other diagram of the vi text editor on the right side.

# While on the first line, press the following key to enter ''COMMAND'' mode: ESC You should see the ''-- INSERT --'' notification disappear indicating that you are in ''COMMAND'' mode. '''NOTE:''' Refer to the table below for a list of the most common '''vi''' ('''vim''') navigation & editing commands: <table cellpadding="5"><tr><th style="border-bottom: 1px solid black;">Key(s)</th><th style="border-bottom: 1px solid black;">Purpose</th></tr><tr><td style="font-family:courier">'''i'''</td><td>Enter '''INPUT''' mode</td></tr><tr><td style="font-family:courier">'''<esc>'''</td><td>Return to '''COMMAND''' MODE</td></tr><tr><td style="font-family:courier">'''x'''</td><td>Delete text to the right in COMMAND mode</td></tr><tr><td style="font-family:courier">'''W'''</td><td>Move forward one word in COMMAND mode</td></tr><tr><td style="font-family:courier">'''B'''</td><td>Move back one word in COMMAND mode</td></tr><tr><td style="font-family:courier">'''dd'''</td><td>Cut line in COMMAND mode</td></tr><tr><td style="font-family:courier">'''yy'''</td><td>Copy Line in COMMAND mode</td></tr><tr><td style="font-family:courier">'''p / P'''</td><td>Paste Cut/Copied Text below/above line in COMMAND mode</td></tr><tr><td style="font-family:courier">'''u'''</td><td>Undo previous editing command</td></tr><tr><td style="font-family:courier">''':help'''</td><td>Display help screen in COMMAND mode</td></tr><tr><td style="font-family:courier">''':x'''</td><td>Save editing changes and exit (in COMMAND mode)</td></tr><tr><td style="font-family:courier">''':w name'''</td><td>Save editing changes to "name" in COMMAND mode</td></tr><tr><td style="font-family:courier">''':q!'''</td><td>Abort editing session and exit (in COMMAND mode)</td></tr></table> Once you can get used to working in INPUT and COMMAND mode, it is easier to perform text editing operations in '''vi''' via ''COMMAND'' mode as opposed to nano!

# Type the following keys to copy the current line: yy

# Type the following key to paste the copied line: p What did you notice?

# Type the following keys: u What did you notice?

# Type the following keys: 3p What did you notice? [[Image:vi-text-editor-b.png|right|200px|thumb|Use a combination of '''arrow''' keys and the '''w''' and '''b''' keys while in COMMAND mode to change the correct words for the '''third''' and '''fourth''' lines.]]

# Use the up or down '''arrow''' keys to move to the second line.

# Type either the '''w''' and/or '''b''' keys to move the cursor to the beginning of the word: '''first'''.

# Type the '''x''' keys to remove the word called '''first'''.

# Type the '''i''' key to enter INSERT mode.

# Type the word: '''second'''

# Press the '''ESC''' key to enter COMMAND mode.

# Repeat steps '''11''' to '''16''' to change the words for line number for lines '''3''' and '''4'''.

# Move to the 4th line (i.e. last line).

# Type the following keys: dd What did you notice? Let's save editing changes and exit the vi text editor.

# Type the following keys: :x and press '''ENTER''' What did you notice?

# Issue the same command that you performed in '''Step #2''' to confirm that you had properly edited that file.

# '''Save''' and '''exit''' your vi editing session. [[Image:vi-text-editor-2.png|right|250px|thumb|The online vi-tutorial provides users "hands-on" experience of using the vi text editor.]]An '''online tutorial''' has been created to give you "hands-on" experience on how to use vi text editor. It is recommended that you run this online tutorial in your Matrix account to learn how to create and edit text files with the vi text editor.

# Issue the following to run the vi online tutorial: /home/jason.carman/vi-tutorial

# In the tutorial menu, select the first menu item labelled "'''USING THE VI TEXT EDITOR'''"

#Read and follow the instructions in the tutorial. Eventually, it will display a '''simulated''' vi environment and will provide you with "'''hands-on'''" practice using the vi text editor. As far as this author is aware, there is NO "hands-on" tutorial for the nano text editor in this particular format.

# When you have completed that section, you will be returned to the main menu. If you want to get extra practice, you can select the menu item labelled "'''REVIEW EXERCISE'''".

# When you want to exit the tutorial, select the menu option to exit the tutorial.

: It is recommended to try both text editors, and choose the text editor that you feel that is easier to use.

===Part 3: Manage & Manipulate Text File Content===

We conclude this tutorial by learning to '''manage''', '''view''' or '''manipulate the display''' of text files. This is HIGHLY ADVISED in case you only want to view contents and '''NOT''' edit text file contents which can cause accidental erasure of data.

'''Perform the Following Steps:'''

# Make certain that you are located in your home directory.

# Refer to the following table of '''Text File Management Commands:''' <table cellpadding="5"><tr><th style="border-bottom: 1px solid black;" width="20%">Linux Command</th><th style="border-bottom: 1px solid black;">Purpose</th></tr><tr><td style="font-family:courier">'''touch'''</td><td>Create empty file(s) / Updates Existing File's Date/Time Stamp</td></tr><tr><td style="font-family:courier">'''cat'''</td><td>Display text file's contents without editing (small files)</td></tr><tr><td style="font-family:courier">'''more , less'''</td><td>Display / Navigate within large text files without editing</td></tr><tr><td style="font-family:courier">'''cp'''</td><td>Copy text file(s)</td></tr><tr><td style="font-family:courier">'''mv'''</td><td>Move / Rename text files</td></tr><tr><td style="font-family:courier">'''rm'''</td><td>Remove text file(s)</td></tr><tr valign="top"><td style="font-family:courier">'''sort'''</td><td>Sorts (rearranges) order of file contents when displayed. Content is sorted alphabetically by default. The '''-n'''''Italic text'' option sorts numerically, '''-r''' performs a reverse sort</td></tr><tr valign="top"><td style="font-family:courier">'''head''' , '''tail'''</td><td>Displays the first / last 10 lines of a text file by default. An option using a value will display the number of lines (e.g. head -5 filename will display first 5 lines, tail -5 filename will display last 5 lines).</td></tr><tr valign="top"><td style="font-family:courier">'''grep'''</td><td>Displays file contents that match a pattern</td></tr><tr valign="top"><td style="font-family:courier">'''uniq'''</td><td>Displays identical consecutive lines only once</td></tr><tr valign="top"><td style="font-family:courier">'''diff''' file1 file2</td><td>Displays differences between 2 files</td></tr><tr><td style="font-family:courier">'''file'''</td><td>Gives info about the contents of the file (e.g. file with no extention)</td></tr><tr><td style="font-family:courier">'''find'''</td><td>To find files matching specified characteristics:  </td></tr></table>

# Issue the following Linux command to create three empty text files in your current directory: touch a.txt b.txt c.txt

# Issue the following Linux command: ls -l a.txt b.txt c.txt Check the size in the detailed listing to confirm that these newly-created files are empty. [[Image:vi-screen-40.png|right|300px|thumb|Nano text editor containing numbers '''1 to 40''' on separate lines.]]

# Use the '''nano''' text editor to edit the empty file called '''a.txt'''. Type the number "'''1'''" and press '''ENTER'''. On the second line, type the number "'''2'''" and press '''ENTER'''. Continue entering increasing number values until you reach the number '''40''' on line 40 (refer to the diagram on the right).

# '''Save''' and '''exit''' your editing session.

# Issue the following Linux command: cat a.txt Can you see all of the contents?

# Issue the following Linux command: more a.txt '''NOTE:''' The '''more''' command uses the same navigation keys as with the '''man''' command (refer to week 1 notes for reference). Try using keys that you used to navigate the man pages. What is the advantage of using the more command?

# Type the letter "q" to exit the ''more'' command.

# Issue the following Linux command: less a.txt Is there any difference between the '''more''' and '''less''' commands? (again press '''q''' to quit)

# issue the following Linux command: sort a.txt Why does the output not look what you expected? Why?

# Issue the following Linux command: sort -n a.txt Try the same command using both the '''-n''' and '''-r''' options to see what happens.

# issue the following Linux command: head a.txt What is the output from this command display?

# issue the following Linux command: head -7 a.txt What is the output from this command display?

# issue the following Linux command: tail a.txt What is the output from this command display? How would you issue this command to display only the '''last line''' contained in that file?

# Issue the following Linux command: grep 2 a.txt What type of output appear? Why did these lines appear (what do they all have in common)? [[Image:end-of-line.png|right|200px|thumb|Edit the '''a.txt''' file and add to the bottom 5 new lines each consisting of the same text: "'''end of line'''".]]

# Edit the '''a.txt''' file and add to the bottom 5 new lines each consisting of the same text: "'''end of line'''" (refer to diagram on right).

# '''Save''' your editing session and '''exit''' your text editor.

# Issue the following Linux command: uniq a.txt What do you notice happened to those newly created lines?

# Issue the following Linux command: cp a.txt a.txt.bk

# Issue the following Linux command: cp a.txt b.txt

# Issue the following Linux command: mv a.txt aa.txt

# Issue a Linux command to view the directory contents. What happened to the file called '''a.txt'''? Why?

# Issue the following Linux command: file b.txt What sort of information did it provide?

# Issue the following Linux command: diff aa.txt b.txt Was there any output? If not, why?

# Issue the following Linux command: diff aa.txt c.txt What do you think is the purpose of this output?

# Issue the following Linux command: find -P . What is the output of this command?

# Issue the following Linux command: rm aa.txt b.txt a.txt.bk c.txt

# Issue the '''ls''' command to verify that these files have been removed.

# Complete the '''LINUX PRACTICE QUESTIONS''' to get additional practice in preparation for tests and quizzes.

= LINUX PRACTICE QUESTIONS =

Jason Michael Carman

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