Basic File Handling

Use the command wget to download one of my server's log files. You need to do:

wget http://linuxzoo.net/data/short.log -O log

Look for file not found errors in this weblog. This is error 404. Although not a perfect method, you can do this by searching for " 404 " in the log. The spaces are important, otherwise a search for "404" would match "404hello" etc.

Once found save all of those to a file called "notfound".

Process the "notfound" file and save a list of only the IP numbers of each log entry. This can be done using

cut -f1 -d" " filename

If you "cat ip" you will see that there are many duplicate IPs shown. The "sort -u filename" command will sort uniquely that file and remove duplicates. It also sorts the entry alpha numerically. What is the last IP printed if this uniqueness processing is applied to the ip file?
Last Unique IP:

How many times does the above IP exist in the full log file "log"?
Count of Last Unique IP:

Save a list of the unique IP numbers from log into a file called uip.

For each line of uip, say how many times that line occurs in log. The output should just be a single number on each line, indicating the count. Save the answer in freq. Use xargs, but make sure in your grep that the IP does not match something shorter, e.g. a line with 10.0.0.1 doesnt match a line of 10.0.0.11.

The problem with the freq file is that you cannot tell which IP has what frequency. Fix that by redoing the above question and making sure the output is in the format of ip,count. For example, "10.0.0.1,5". Save the answer to freq2

Hint: the xargs needs to be in the format:

sh -c "echo -n {},;grep -c '{} ' log"