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I'm working on a public server, which offers games designed to teach people Linux and ethical hacking skills. The goal of each level (so far) has been to find the ssh password to the following level w/ various commands suggested as possibly being useful in accomplishing this task. I'm currently working on a level, which listed the following as the goal:

The password for the next level is stored in a file somewhere under the 
inhere directory and has all of the following properties:
     human-readable
     1033 bytes in size
     not executable

The suggested commands are: ls, cd, cat, file, du, find

I found two separate questions/answers on Unix & Linux StackExchange pertaining to this exact exercise. These can be found here and here. Both sets of commands output essentially the same information. For instance, from the first link, the accepted answer and output was:

bandit5@bandit:~/inhere$ find . -type f -size 1033c ! -executable -exec file {} + | grep ASCII                          
./maybehere07/.file2: ASCII text, with very long lines

I decided to play w/ this command a bit, so first, I removed grep from the command, then ran it again. I then removed the non-executable switch and the file command and ran it again.

bandit5@bandit:~/inhere$ find . -type f -size 1033c ! -executable -exec file {} +                                       
./maybehere07/.file2: ASCII text, with very long lines

bandit5@bandit:~/inhere$ find . -type f -size 1033c                                                                     
./maybehere07/.file2

As is plain to see, the shortest version of this command returns the exact information I was searching for. The second link above from Unix & Linux StackExchange is an even longer and more exacting command returning the same information as the shortest version of the command above.

Is there a time when these longer commands might prove useful to retrieve output in a similar situation? Would these longer commands narrow down the sought after answer, while parsing out output that the shorter command might not?

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To answer your question (despite the downvote) yes this is just because the person who first wrote that command was trying to use all the information available to them. The question states that the file is human-readable, 1033 bytes in size, and not executable. The original command was:

find . -type f -size 1033c ! -executable -exec file {} + | grep ASCII

So lets break this down into parts:

-type f means you're looking for a file (as opposed to a directory).

-size 1033c means you're looking for a file that is 1033 bytes.

! -executable means you are looking for a file that is not executable.

-exec file {} + means you want to execute the file command on each file found by find.

| grep ASCII here you're piping the output of the previous command into grep to search for only lines containing ASCII.

I've created 3 files that are each 1033 bytes, file1 is binary data, file2 is the file you're looking for and file3 is a copy of file1 but is marked as executable. In this directory here's the output of your suggested commands:

jon@jon-HP-Pavilion-15-Notebook-PC:~/temp$ find . -type f -size 1033c ! -executable -exec file {} + | grep ASCII
./file2: ASCII text, with very long lines
jon@jon-HP-Pavilion-15-Notebook-PC:~/temp$ find . -type f -size 1033c ! -executable -exec file {} +
./file2: ASCII text, with very long lines
./file1: data
jon@jon-HP-Pavilion-15-Notebook-PC:~/temp$ find . -type f -size 1033c
./file2
./file1
./file3

As you can see with multiple files these commands behave very differently, the reason they seem the same in your test environment is because there is only one file that is 1033bytes (which to be fair is probably also the case in reality, but then again in reality you often don't know the exact size of a file).

  • I'm not certain why you received a downvote. It wasn't from me. I found your answer to be quite helpful and spot on. It reinforced the idea that in certain instances, you might end up w/ similar filetypes, thus the need to use more tools at your disposal. As I mentioned in my OP, I think that in this instance, the environment was set up to teach the basics in a way so as not to create the need for more complex commands. After all, this was level five of 34, so it's still the early-going. Thanks very much for your answer! – jmg999 Apr 18 at 2:17
  • @jmg999 The downvote I was referring to was the one for your question, I disagree with the downvote because StackExchange is a learning community and as such I think questions asking to further understanding are great, but obviously some people disagree. Although for future reference the preferred way of giving thanks on StackExchange is by accepting (and if you can) up-voting an answer. This keeps the comments clean and helps the contributors. Cheers and happy learning! – Dude Random21 Apr 18 at 19:08

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