System Level Programming Lab Assignment 4 - Part 2

CSC3320 System Level Programming
Lab Assignment 4 - Part 2 (Out of lab)

Purpose: Practices on the grep, fgrep, egrep, sed , awk, and sort commands for text
processing.
Note: Please follow the instructions below, and write a report by answering the questions and
upload the report (named as Lab4_P2_FirstNameLastName.pdf or .doc) to the Google
Classroom Out of Lab Assignment folder
Please add the lab assignment NUMBER and your NAME at the top of your file sheet.
The following table is from Wikipedia. It shows the eleven highest mountains
in Georgia.
Brasstown Bald, (summit),4784,feet,Union County
Rabun Bald, (summit),4696,feet,Rabun County
Dick's Knob, (summit),4620,feet,Rabun County
Hightower Bald, (summit),4568,feet,Towns County
Wolfpen Ridge, (ridge high point),4561,feet,Towns and Union
Counties
Blood Mountain, (summit),4458,feet,Union County
Tray Mountain, (summit), 4430,feet,Towns County
Grassy Ridge, (ridge high point),4420,feet,Rabun County
Slaughter Mountain, (summit),4338,feet,Union County
Double Spring Knob, (summit),4280,feet,Rabun County
Coosa Bald, (summit),4280,feet,Union County
In above table, each line contains 5 fields separated by comma. Open your
terminal and connect to snowball server. After that, go to directory Lab4 (cd
~/Lab4) and please download the file " mountainList.txt" by the following
command (internet access required):
cp /home/frondel/Public/mountainList.txt mountainList.txt
Be sure it succeeds using “ls” to see the file name “mountainList.txt” listed.
1) Use grep to print all lines where the mountains are at Towns or Union
County.
1
Sample Output
2) Use wc and grep to count the number of mountains located at Rabun
County.
Hint: please use pipe | .
Sample Output
3) Finish task 2) by using only grep.
Hint: open the manual page of grep, and check -c option.
4) A. Type command sed ‘s/ridge high point/r.h.p./p’ mountainList.txt
and execute it. Then attach a screenshot of the output.
B. Type command sed -n ‘s/ridge high point/r.h.p./p’ mountainList.txt
and execute it. Then attach a screenshot of the output.
C. Open the manual page of sed and describe what does –n do in sed?
D. Describe what does the sed command in (B) do?
5) Use sed to remove the leading spaces in "mountainList.txt" and print out
the processed lines.
6) Finish task 5) and save the output to file "newList.txt".
7) Use sed to list the lines beginning with white spaces in "mountainList.txt".
Sample Output
2
8) Use sed to delete the lines where the mountains are only at Union County
in "mountainList.txt".
Sample Output
9) Use sed to remove the middle three fields in each line of
"mountainList.txt". Hint: Think about the meaning of regex '[^,]'
 sed -r 's/,([^,]*){3},/,/g' public/mountainList.txt
Sample Output
10) Use awk to finish task 9).
11) Use sed to insert a new line “Table: Eleven highest mountains in Georgia”
at the beginning of "mountainList.txt".
12) Use sort to print out the sorted lines in alphabetical order according to the
names of mountains.
13) Use sort to print out the sorted lines in descending order according to the
height of mountains.
14) “When a pattern groups all or part of its content into a pair of parentheses,
it captures that content and stores it temporarily in memory. You can
reuse that content if you wish by using a back-reference, in the form:\1
or $1, where \1 or $1 reference the first captured group” (Refer to [1]). For
example, the following command add a colon between Union and County
sed -E ‘s/(Union)\s(County)/\1:\2/g’ mountainList.txt
Attach a screenshot of the output of the above sed command.
15) Now can you write a command to finish task 9) using sed with backreference?
Useful Links:
[1] Introducing Regular Expression - Capturing Groups and Backreferences https://www.safaribooksonline.com/library/view/introducingregular-expressions/9781449338879/ch04.html
[2] Drew's grep tutorial
http://www.uccs.edu/~ahitchco/grep/
[3] Grep and Regular Expressions!
http://ryanstutorials.net/linuxtutorial/grep.php
[4] Web Scraping with Regular Expressions
https://www.datascraping.co/doc/22/regular-expression