Linux

Here are some explanations on file systems, directories, and devices between windows and Linux which people might not understand the terms and not migrate to Linux for some reason.

Coming to Linux from an OS like Windows requires you to learn not only how to operate, but how to understand what is going on in your computer. Many people have a good understanding of the underlying DOS directory structure and how it operates, so switching between OS’s such as mac-os, W8, and W10 are relatively seamless. However, Linux demonstrates a new way of thinking for many users.

An easy way to keep tabs on your system is through the program top. The top is a little app that can display the processes currently running, how much RAM, processor and how much CPU time they are taking (just like ps aux). First, let’s start off by starting it up.

[root@rd ~]# top

This should bring up a nice looking program that shows us much of what ps aux shows us but updated every second. You can change the time between updates by pressings, then typing in the seconds between updates (Note: you can use decimal numbers like 0.5). To switch to command mode display, hit c, and to sort by CPU time hit T.
The top is very useful in tracking what your resource hogs are, and what your RAM and Swap usage is. Play with it, the top’s a neat little program.

Scheduling in Linux…

Linux comes equipped with scheduling tools. Tools that will let you get a full night’s rest and still have that backup program automatically run at 3am on the dot, and even send us an email letting us know about any appointments.

1. Using the at utility

The at command is used for jobs that need to be run only once. at is an interactive program and it takes in an argument, which is the time and date that you want the job to be run. All outputs of at are sent by email. So let’s say it’s 1pm, and we have a meeting at 3pm. In order to be reminded of this meeting at 2:30pm, we can type:

How do you know if someone is probing your network?  Logs are a great place to start, especially your FW-1 logs.  Unfortunately, those logs can be difficult and time consuming to sift through (especially if you are logging 400+ B every day). Wouldn’t it be great if there was an automated method of alerting you?

There are a variety of different probes and attacks black-hats will attempt. he types we will be focusing on is port scans. Port scans are where an individual attempt to connect to a variety of ports to identify what services a system is running.  The scans can be used on a specific target or used to scan entire IP ranges, often chosen at random.  This is one of the most popular information gathering methods used by black-hats today as it identifies what ports and services are open.

There are two types of filesystems you will need to learn how to make in order to get your Linux multi-partition system up and running are swap and ext2.

–Creating a swap filesystem–

The command for this is mkswap. You have to be root to run this, of course. If you get a “command not found” error, then you need to enter the full path, which is: /sbin/mkswap

The options for mkswapare (ripped from the man page):