Question

Instructions:

Using Unix programming language and regular expressions,

1. how many unique ip addresses were seen note: we only want to look at ipv4 addresses
2. which was most commnly seen ip address
on the piece of access.log file below

66.249.75.132 - - [18/Jun/2018:06:41:00 -0500] "GET /~rcoleman/Common/History/Images/?C=N;O=D HTTP/1.1" 200 1976 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
5.255.250.23 - - [18/Jun/2018:06:41:23 -0500] "GET /~rcoleman/Common/CodeVault/Code/DesignPatterns/Images/DP16-Builder.jpg HTTP/1.1" 304 182 "-" "Mozilla/5.0 (compatible; YandexImages/3.0; +http://yandex.com/bots)"
5.255.250.23 - - [18/Jun/2018:06:41:28 -0500] "GET /~rcoleman/CS121/CourseInfo/Images/WinExp.jpg HTTP/1.1" 304 180 "-" "Mozilla/5.0 (compatible; YandexImages/3.0; +http://yandex.com/bots)"
148.108.96.32 - - [18/Jun/2018:06:41:43 -0500] "GET /~rcoleman/Common/Basics/Images/ASCII_Table.jpg HTTP/1.1" 200 144715 "https://www.bing.com/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0"
5.255.250.23 - - [18/Jun/2018:06:42:41 -0500] "GET /~delugach/Courses/H399-01/License%20Agreement%20for%20Acrobat HTTP/1.1" 200 12667 "-" "Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots)"
5.255.250.23 - - [18/Jun/2018:06:42:59 -0500] "GET /~rcoleman/Common/CodeVault/Code/DesignPatterns/Images/DP03-Decorator.jpg HTTP/1.1" 304 182 "-" "Mozilla/5.0 (compatible; YandexImages/3.0; +http://yandex.com/bots)"
49.36.1.71 - - [18/Jun/2018:06:43:22 -0500] "GET /favicon.ico HTTP/1.1" 301 4121 "https://www.cs.uah.edu/~rcoleman/Common/C_Reference/C++%20For%20DUMMIES.pdf" "Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3452.0 Safari/537.36"
148.253.182.198 - - [18/Jun/2018:06:44:00 -0500] "GET /~rcoleman/CS121/ClassTopics/Images/Operators02.jpg HTTP/1.1" 200 54617 "https://www.bing.com/" "Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko"
49.36.1.71 - - [18/Jun/2018:06:43:21 -0500] "GET /~rcoleman/Common/C_Reference/C++%20For%20DUMMIES.pdf HTTP/1.1" 200 8103354 "https://www.google.co.in/" "Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3452.0 Safari/537.36"
66.249.75.130 - - [18/Jun/2018:06:44:42 -0500] "GET /~rcoleman/Common/History/Images/Pic20_ABC.jpg HTTP/1.1" 304 181 "-" "Googlebot-Image/1.0"
179.7.54.141 - - [18/Jun/2018:06:44:53 -0500] "GET /~rcoleman/Common/C_Reference/C++%20For%20DUMMIES.pdf HTTP/1.1" 200 8085570 "-" "Dalvik/2.1.0 (Linux; U; Android 7.0; SM-J730GM Build/NRD90M)"
175.158.232.110 - - [18/Jun/2018:06:45:58 -0500] "GET /~rcoleman/CS121/ClassTopics/Images/CompSys10.jpg HTTP/1.1" 200 217846 "https://www.google.com.ph/" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36"
5.255.250.23 - - [18/Jun/2018:06:46:03 -0500] "GET /~rcoleman/Common/SoftwareEng/Images/UML_01.jpg HTTP/1.1" 304 181 "-" "Mozilla/5.0 (compatible; YandexImages/3.0; +http://yandex.com/bots)"
5.255.250.23 - - [18/Jun/2018:06:46:23 -0500] "GET /~dhardin/cs_100/Animations/frmMoveBall_GUI.frm HTTP/1.1" 200 2066 "-" "Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots)"
216.244.66.197 - - [18/Jun/2018:06:47:14 -0500] "GET /robots.txt HTTP/1.1" 301 577 "-" "Mozilla/5.0 (compatible; DotBot/1.1; http://www.opensiteexplorer.org/dotbot, [email protected])"
157.55.39.241 - - [18/Jun/2018:06:47:37 -0500] "GET /~rcoleman/Common/Basics/Images/Pointers03.jpg HTTP/1.1" 200 76104 "-" "Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)"
41.190.3.133 - - [18/Jun/2018:06:47:51 -0500] "GET /~rcoleman/Common/History/History.html HTTP/1.1" 200 9592 "http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=14&ved=0ahUKEwjNw_ODkt3bAhWkB8AKHfbUCMwQFghnMA0&url=http%3A%2F%2Fwww.cs.uah.edu%2F~rcoleman%2FCommon%2FHistory%2FHistory.html&usg=AOvVaw1na6HxGz_OCQSHXgI3jn1L" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:52 -0500] "GET /~rcoleman/Common/History/Images/Pic02_RomanAbacus.jpg HTTP/1.1" 200 43539 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:52 -0500] "GET /~rcoleman/Common/History/Images/Pic01_AncientTimes.jpg HTTP/1.1" 200 40097 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:52 -0500] "GET /~rcoleman/Common/History/Images/Pic03_JohnNapier.jpg HTTP/1.1" 200 39131 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:52 -0500] "GET /~rcoleman/Common/History/Images/Pic06_WilliamOughtred.jpg HTTP/1.1" 200 49153 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:52 -0500] "GET /~rcoleman/Common/History/Images/Pic05_SlideRule.jpg HTTP/1.1" 200 71314 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"
41.190.3.133 - - [18/Jun/2018:06:47:53 -0500] "GET /~rcoleman/Common/History/Images/Pic04_NapiersBones.jpg HTTP/1.1" 200 53637 "http://www.cs.uah.edu/~rcoleman/Common/History/History.html" "Mozilla/5.0 (Windows NT 6.1; rv:36.0) Gecko/20100101 Firefox/36.0"

Answer 1

Answer 1
***********

grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' access.log | uniq

Answer 2
************

grep -o "[0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+" access.log | sort | uniq -c | sort -n

if you have any doubt then please ask me without any hesitation in the comment section below , if you like my answer then please thumbs up for the answer , before giving thumbs down please discuss the question it may possible that we may understand the question different way and we can edit and change the answers if you argue, thanks :)