M$07\mathrm{.}03-$ ANSWER SHEET $-$ COMPARING AND MANIPULATING TEXT

ASSIGNMENT OBJECTIVES:

On completing this lab, you should be able to:

$$ Compare text from various files using comm and diff.

$$ Manipulate text using paste, join and cut..

PART $1$ COMPARING FILES

INSTRUCTIONS:

The Linux command line is incredibly powerful and efficient at processing text in files. This lab will introduce you to

several command line tools used to compare and manipulate text in files. You will also be required to complete tasks

previously covered in prior sections and in class. This lab will use some of the directories and files used in the

M$7-$Organizing Text lab. Perform the task being requested on your vSphere virtual machine. Provide the requested

answer or screenshot as indicated in the task.

TASK

Task $1$

Read the handout on accessing the Virtual Lab in Canvas to access your virtual machine. Log in to the sysadmin

account with the password netlab$123$ and open the terminal program.

Task $2$

Change your working directory to the TextFiles directory which was created in a previous lab. If you do not

have this directory please refer to the previous lab.

Task $3$

Create two text files named file$1$ and file$2.$

file$1$ file

$001$

$056$

$127$

$258$

INFO $1111$: Linux I

INFO$-1111$: LINUX I $2$

file$2$ file

$002$

$056$

$167$

$369$

Capture a screenshot showing you successfully completed this task.

Add your screenshot for this task on the answer sheet as Screenshot $1.$

Task $4$

The comm command compares $2$ similar sorted files. Use the following command:

comm file$1$ file$1$

This command will output $3$ columns. The first column $($left$)$ displays text lines uniq to file$1.$ The second column

$($middle$)$ displays lines unique to file$2$ and the $3$rd column $($right$)$ displays the lines common to both files.

Task $5$

To suppress or hide one of the columns of the output for comm use the $-1,-2$ or $-3$ option. For example, to

suppress the third column execute the following command:

comm $-3$ file$1$ file$2$

INFO $1111$: Linux I

INFO$-1111$: LINUX I $3$

Task $6$

Use the comm command to compare file$1$ and file$2$ and suppress the first column of the output.

Capture a screenshot showing you successfully completed this task.

Add your screenshot for this task on the answer sheet as Screenshot $2.$

Task $7$

Make a copy of the avengers.txt file created in a previous assignment. Name the copy avengers$2.$txt$.$

Task $8$

Open the new avengers$2.$txt file in vim and delete $2$ lines from the file so it differs from the original

avengers.txt$.$ Save and close the file

Task $9$

Use the comm command to compare the avengers.txt and avenger$2.$txt file. The comm command requires files

to be sorted. Since the avengers text files are not sorted you will receive an error. What error do you receive.

Submit your answer for this task on the answer sheet as Answer $1.$

Task $10$

To override the error received by unsorted files, use the $--$nocheck$-$order option with comm.

comm $--$nocheck$-$order avengers.txt avengers$2.$txt

Capture a screenshot showing you successfully completed this task.

Add your screenshot for this task on the answer sheet as Screenshot $3.$

INFO $1111$: Linux I

INFO$-1111$: LINUX I $4$

Task $11$

By default, the comm command separates $($delimits$)$ the output columns with a tab. To change the delimiter

from a tab to another character, use the $--$output$-$delimiter option. For example, to separate columns using the

plus sign use the following command.

comm $--$nocheck$-$order $--$output$-$delimiter$=+$ avengers.txt avengers$2.$txt

Task $12$

Compare the $2$ avengers files separating each column with commas $(,).$

Capture a screenshot showing you successfully completed this task.

Add your screenshot for this task on the answer sheet as Screenshot $4.$

Task $13$

Like the comm program, diff is used to detect the differences between files. diff has a lot more features than

comm. It is often used by programmers to examine changes between different versions of code. diff also has

the ability to create diff files or patches that are used by programs to convert one version of a file to another.

If we want compare avengers.txt to be the same as avengers$2.$txt$,$ we can see what we need to change with

the following command:

diff avengers.txt avengers$2.$txt

You many have different results with your output than the image above based upon how you changed your

avengers$2.$txt file.

Reading the output of the diff command can be challenging. The can help interpret the output.

$9$d$8-$ The $9$ represents the $9$th line, the d represents delete and $8$ represents what would appear in the file

being compared. So if the $9$th line $($spider$-$man$)$ was deleted from the avengers.txt file then it would be the

INFO $1111$: Linux I

INFO$-1111$: LINUX I $5$

same as line $8$ in the avengers$2.$txt file.

$<$ spider$-$man $-$ The $<$ represents the file listed first $($avengers$.$txt is left of avengers$2.$txt in the diff command$).$

spider$-$man is the line that is different.

$11$d$9-$ The $11$ represents the $11$th line. The d represents delete and $9$ represents what would appear in the $9$th