Quick log analysis

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Step 1: Download Putty from here:
http://the.earth.li/~sgtatham/putty/latest/x86/putty.exe


Step 2: Use putty with the information below to connect to your Linux server
IP Address:	107.191.39.106
Protocol:	ssh
Port:		22
username:	eayila
password:	eayila123





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# Log Analysis with Linux command-line tools #
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The following command line executables are found in the Mac as well as most Linux Distributions.

cat –  prints the content of a file in the terminal window
grep – searches and filters based on patterns
awk –  can sort each row into fields and display only what is needed
sed –  performs find and replace functions
sort – arranges output in an order
uniq – compares adjacent lines and can report, filter or provide a count of duplicates


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# Cisco Logs #
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-----------------------------Type this-----------------------------------------
wget https://s3.amazonaws.com/infosecaddictsfiles/cisco.log
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AWK Basics
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To quickly demonstrate the print feature in awk, we can instruct it to show only the 5th word of each line. Here we will print $5. Only the last 4 lines are being shown for brevity.

-----------------------------Type this-----------------------------------------
cat cisco.log | awk '{print $5}' | tail -n 4
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Looking at a large file would still produce a large amount of output. A more useful thing to do might be to output every entry found in “$5”, group them together, count them, then sort them from the greatest to least number of occurrences. This can be done by piping the output through “sort“, using “uniq -c” to count the like entries, then using “sort -rn” to sort it in reverse order.

-----------------------------Type this-----------------------------------------
cat cisco.log | awk '{print $5}'| sort | uniq -c | sort -rn
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While that’s sort of cool, it is obvious that we have some garbage in our output. Evidently we have a few lines that aren’t conforming to the output we expect to see in $5. We can insert grep to filter the file prior to feeding it to awk. This insures that we are at least looking at lines of text that contain “facility-level-mnemonic”.

-----------------------------Type this-----------------------------------------
cat cisco.log | grep %[a-zA-Z]*-[0-9]-[a-zA-Z]* | awk '{print $5}' | sort | uniq -c | sort -rn
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Now that the output is cleaned up a bit, it is a good time to investigate some of the entries that appear most often. One way to see all occurrences is to use grep.

-----------------------------Type this-----------------------------------------
cat cisco.log | grep %LINEPROTO-5-UPDOWN:

cat cisco.log | grep %LINEPROTO-5-UPDOWN:| awk '{print $10}' | sort | uniq -c | sort -rn

cat cisco.log | grep %LINEPROTO-5-UPDOWN:| sed 's/,//g' | awk '{print $10}' | sort | uniq -c | sort -rn

cat cisco.log | grep %LINEPROTO-5-UPDOWN:| sed 's/,//g' | awk '{print $10 " changed to " $14}' | sort | uniq -c | sort -rn
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