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UNIX/Linux Fundamentals Journal

February 22, 2016

The biggest challenge for me this week was observation. I can't say that I ever realized how unobservant I am. So many HOURS were spent on rabbit trails because I didn't think before i sought answers. I did pretty well on the first level finding the README file before I got too side tracked, but it was all up hill from there.

The next step wasn't too bad. Reading the documentation comments in the file was extremely straight forward. But the step of actually getting the program to run was a nightmare. I wasn't sure what standard input and output were. I think I tried every combination and format of commands to get this to work and spent many hours of frustration over a period of about 3 days. So glad I started this assignment early.

I remembered from my past experience with Unix that there were a few different ways to redirect output. There is the pipe, which from the outcome of this weeks assignment I am assuming is the one that is used to direct output from one command to another command or a program. There is the > symbol which I think directs output to a text file that it creates. or overwrites. and there is a » that appends output to already existing text in a file.

The challenge of getting the next password to work deserves mentioning. Once I got the message decoded, I tried copy and pasting the password into the extraction. No go. I am not sure why this didn't work, but trying to type it in manually was a tedious process. The spaces and punctuation in addition to the obstacle of not being able to SEE what I was typing resulted in over 10 attempts to get this password right. UGH!

Once I got the files extracted, using one of the formerly mentioned direction symbols, I catted the contents of all four files to a single, new file. Then the challenge of reordering the lines of the file to create something that made sense. I started by looking in the text on Vi and Vim but was unable to find what I was looking for, so I again resorted to google. “Sort lines vi Unix”. I don't know if it is just me, and it feels like cheating, but I so often find search engines to be the best “go to” for finding information quickly.

After finishing the submission for this week, I posted the question about the repository. It was good review for me to relearn the routine of using Mercurial. The more programming and CLI I do, the more I understand the value of programs like this.

In the process of working on this weeks assignment, I decided to create an outline of each step I took to help me to organize my thoughts in real time to use as a reference when it was time to write this weeks journal entry. In doing this, as I do with all my files, I saved the progress in my Dropbox account. As I write this, I am using a computer I don't usually work on and as such, I am accessing my Dropbox account directly from their website. As I loaded the file in, I discovered that dropbox also keeps revisions of file changes that you can access on your account.

With more could-based storage, the integration of revision control seems to be becoming the norm.

February 8, 2016

My dream job would be a professional hacker. I would love to get paid by companies and agencies to try to break into their systems to expose any vulnerabilities. Most likely this would be why I love shows like Person of Interest. This week’s assignment was interesting and exciting for me. I never thought about layers of compilation and encryption before. To be honest, I'm not even sure I realized it was even possible, at least not without errors or loss of integrity. But now I wonder if this is how security is actually handled. Multiple layers of encryption?

I probably made this week’s project more complicated than it needed to be. I did a file command on the riddle.html file. I saw that it was compressed with gzip so I looked at the manual for gzip and learned that guy zip was the command I needed. I ran the command and got an “unknown suffix” error message. This confused me because we just learned that extensions don't exist in UNIX, but I assumed that this had something to do with the error message. I renamed the file (mv) from riddle.html to riddle.gz. I reran the gunsight and it worked. Layer one down.

I continued this process of using the file command and extracting as necessary from the consecutive layers of encryption. When I got to the last layer, I first use the cat command to look at the file contents and caught the text BASE64 at the start of the file. So true to my nature, I googled it. I found a website, www.base64decode.org that will decode or encode ASCI text using Base64. I copied the text from the dinosaur_with_hats.mp4 file and pasted it into this sites decoder. That was the first time I realized I had gotten into the puzzle box. I was so excited. Then it was a little bit of a challenge to find the right command in Unix to do it the way it was SUPPOSED to be done. It may have been the long way to do things, but I learned a lot and had so much fun in the process.

I can’t wait to get further into this course. I am really looking forward to the problem solving aspect of it. Solving puzzles is one of my favorite things to do in my spare time.

February 1, 2016

Challenging doesn’t begin to describe this week. After a lot of google searching, a lot of man commands, and numerous typos, I think I finally got it. I have used zip files many times, and I did understand generally how they work. This week, however, I gained a much greater understanding of an archive. I guess before this week I was under the impression that an archived file was essentially the same thing as a compressed file. I have a much clearer understanding of the difference. The biggest challenge for me this week was understanding what the rev and tac commands do. I Googled them to look for examples and hopefully gain a much better understanding of how they work. The best examples I found were on thegeekstuff.com:

$ cat thegeekstuff.txt 1. Linux Sysadmin, Scripting etc., 2. Databases Oracle, mySQL etc., 3. Hardware 4. Security (Firewall, Network, Online Security etc) 5. Storage 6. Cool gadgets and websites 7. Productivity (Too many technologies to explore, not much time available) 8. Website Design 9. Software Development 10. Windows Sysadmin, reboot etc., 11. Adding 1's and 0's

$ tac thegeekstuff.txt 11. Adding 1's and 0's 10. Windows Sysadmin, reboot etc., 9. Software Development 8. Website Design 7. Productivity (Too many technologies to explore, not much time available) 6. Cool gadgets and websites 5. Storage 4. Security (Firewall, Network, Online Security etc) 3. Hardware 2. Databases Oracle, mySQL etc., 1. Linux Sysadmin, Scripting etc.,

$ rev thegeekstuff.txt ,.cte gnitpircS ,nimdasyS xuniL .1 ,.cte LQSym ,elcarO sesabataD .2 erawdraH .3 )cte ytiruceS enilnO ,krowteN ,llaweriF( ytiruceS .4 egarotS .5 setisbew dna stegdag looC .6 )elbaliava emit hcum ton ,erolpxe ot seigolonhcet ynam ooT( ytivitcudorP .7 ngiseD etisbeW .8 tnempoleveD erawtfoS .9 ,.cte toober ,nimdasyS swodniW .01 s'0 dna s'1 gniddA .11

This is very interesting, although I am still not sure that I understand where the rev command can be at all useful, I see where tac could be used to order log files, for example. And although I have never formally been diagnosed, this weeks project has me convinced I have aixelsyd, I mean dyslexia.

Another discovery I made inadvertently this week was that the dir command that I am used to using in DOS also appears to work in Unix. It does the same thing as the ls command without the color coding.

I also had some technical issues with one of my terminal sessions. I got an error that seemed to indicate an issue with some stopped processes and it would not let me “exit” the session. So I tried using the kill command which I remembered from my so-long-ago Unix days, but I fumbled through it and in the end I am not even sure that my “playing” with that command is what eventually resolved the issue.

January 27, 2016

Well, this first week has been quite a roller coaster. I have used Unix before. My first job in this are was as a Marketing Assistant. While working in that job, I slowly migrated to the position of Unix System Administrator. I was quite proficient in the basics of Unix, but alas, this was about 28 years ago. Staring out this week, much of the material does look familiar and it is coming back quite easily. However, I have been quickly realizing the VERY basics is about all I remember, so the rest of this course should be interesting.

One of the biggest challenges for me is going to be wrapping my head around the statement I read in the text: “One of the wonderful things about UNIX….Practically everything on the UNIX filesystem is a file. A directory, then, is a file that contains the locations of other files.” WHAT?? Coming from a very heavy DOS background, this does not compute. I am really hoping the reprogramming on this one isn't going to be painful. =S

blog/spring2016/asutton5/journal.1456196990.txt.gz · Last modified: 2016/02/23 03:09 by asutton5