Bash, making things easier.

Following on from my post last night about WGet and YouTube-DL, we’ve learned how to enable Bash on Windows 10. Now, this is an extremely useful thing to do, because it empowers you to use commands that are not native on Windows (or as a Linux fanboy would say, M$).

So, just so you all get a better understanding of the improved functionality of bash, we’re going to make some comparisons and examples.

I’m not going into detail – there is far too much to cover.

Network Monitoring – netstat.


On a windows box, to see current usage per process, the easiest method is to run:

netstat -a -b

Which will return a string similar to this:

 [chrome.exe]
     TCP 192.168.0.15:52581 192.0.78.13:https     ESTABLISHED
 [chrome.exe]
     TCP 192.168.0.15:52971 192.0.78.23:https     ESTABLISHED
 [chrome.exe]
     TCP 192.168.0.15:52972 192.0.76.3:https      ESTABLISHED

Rather simple to do, and allows you to see what process is responsible for what traffic, and what protocol it is using.

GNU + Linux supports netstat, but has a complete different syntax for the commands. To see connections with the process, simply run the following:

root@DESKTOP-3O8E0L8:/home/nanky# netstat -p


Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name

 

It returns a little more intuitive data (in my opinion). For example, we can then dictate by interface the data we wish to see by adding -i to the command:

netstat -i

This is an advantage over Windows. But let us get to the killer feature:

netstat -a -v -w -r

The following flags are used:

 -a, --all
 Show both listening and non-listening sockets. With the --interfaces option, show interfaces that are not up

--verbose , -v
 Tell the user what is going on by being verbose. Especially print some useful information about unconfigured address families.

--wide , -W
 Do not truncate IP addresses by using output as wide as needed. This is optional for now to not break existing scripts.

Thus allowing this command to return more valuable information, depending on the situation. However, there is a better tool: bmon and nethogs.

bmon

Start by issuing the following command:

sudo apt-get install bmon

 

Once installed, you should always look at the man page:

man bmon

 

Using bmon allows you to view the usage and statistics per interface, such as:

BMON Capture

Of course, there are other tools to conquer these tasks out there – I would strongly suggest you read this post outlining other sysadm tools available to you.

 

Automation, crontabs.


As opposed to the clunky Windows Task Scheduler, Linux uses Cron Jobs to execute tasks.

You’ll need to have bash running for CronJobs to work on Windows.

Pretty self explanatory, create a script or command you want to execute, and add it to the scheduler. Here it the default example provided to you:

# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/

You guessed it, the stars represent time:

# m h dom mon dow command

The tar -zcf portion is the code it executes. Pretty self explanatory. 7:30am, every week for example:

crontab -e
30 7 * * 1 /my/command/to/execute/yo.sh

You get this. Easy stuff.

 

Task Maintenance – task.


Okay so this one’s not so critical, I just love this application. TaskWarrior. Tasks is a super simple yet super powerful CLI driven task manager.

sudo apt-get install task

 

There we go, you’ve installed it. Let’s add our first task:

nanky@DESKTOP-3O8E0L8:~$ task P:H  due:31 project personal add edit this css

Now let’s view our task:

 ID Age P Due Description Urg
 2  26s H  4w edit this css

Pretty simple method to view the task at hand. Now we want to view the task with the ID ‘2’:

task id 2

Which will return the following:

Name Value
ID 2
Description change task 1
Status Pending
Entered 2017-09-27 23:50:56 (1min)
Last modified 2017-09-27 23:50:56 (1min)
Virtual tags PENDING READY UDA UNBLOCKED LATEST PRIORITY
UUID 34c4cf80-a857-4123-a463-4c4bcc44b591
Urgency 6
Priority H

UDA priority.H 1 * 6 = 6
 ------
 6

You can sync your tasks across multiple devices, too! Just view their usage examples, and you’ll get the feel for how complex you can make the tool.

Lastly, text editing.


I cannot live without GNU Nano. Yes, you could use Vim but the simplicity of Nano amazes me.

For example, let’s edit a file and close it, all without needed to locate it, open, manually save and confirm dialogs:

nano /mnt/c/path/to/file/yo.txt

It is literally that simple, and you can interact with files stored on Windows natively.

That’s it.

You pretty much get the picture; CLI > GUI.

 

Just read:

  1. 20 Command Line Tools to Monitor Linux Performance
  2. Best Linux Command-Line Tools For Network Engineers
  3. Top 5 Linux Utilities for Network Engineers

 

 

 

 

 

Learning PowerShell with Michael.

At the present, I am refining my PowerShell usage, updating my scripts to make the code more readable and slowly learning new methods to do things easier, and faster. I’ve been on several forums relating to PowerShell and am quite active (you may have found this blog from there?), and thought I’d make my own post.

Whilst I’ll attempt to be as thorough as possible (we all know I do not vet my own documents), this shall not be an all-encompassing guide/post on PowerShell. The post will briefly cover:

  1. What is Windows Management Framework 5.0?
  2. IDE(s) and their benefits
  3. Using Variables
  4. Using Functions

So, let’s get into it.

What is Windows Management Framework 5.0?

The technical answer is:

Windows Management Framework (WMF) is the delivery mechanism that provides a consistent management interface across the various flavors of Windows and Windows Server.

Source

In easier terminology, it is a distinct sub-set of Windows tools designed for automation, maintaining and auditing Windows PC(s), and primarily, Windows Servers.

Think of WMF as a toolbox, that houses tools:

In Windows, .NET Framework and PowerShell are implemented through the Enable/Disable Features option.

Of course, you should be able to just use DISM to enable the feature as well:

Dism /online /enable-feature /featurename:NetFx3 /All /Source:F:\sources\sxs /LimitAccess
  •  Where F:\sources\sxs is your installation directory SXS folder.

Note the following availability:

Operating System Version WMF 5.1 WMF 5.0 WMF 4.0 WMF 3.0 WMF 2.0
Windows Server 2016 Ships in-box
Windows 10 Ships in-box Ships in-box
Windows Server 2012 R2 Yes Yes Ships in-box
Windows 8.1 Yes Yes Ships in-box
Windows Server 2012 Yes Yes Yes Ships in-box
Windows 8 Ships in-box

IDE(s) and their benefits

Integrated Development Environments, or “IDE”, are different to the Integrated Scripting Environment, “ISE”, slightly. For example, the following quote depicts IDE:

An IDE normally consists of a source code editorbuild automation tools and a debugger. Most modern IDEs have intelligent code completion. Some IDEs, such as NetBeans and Eclipse, contain a compilerinterpreter, or both.

ISE is rather limited, as:

  • It is designed for PowerShell only (as far as I am aware);
  • There is no real debugger, just console output and;
  • It was designed for Microsofts Operating System Only (Can be run on Linux and OSX though)

Whilst I do not dislike the ISE for PowerShell, it’s not one I would suggest you use. Sure, it has all the cmdlets housed in a neat menu, depicting what category they fall under, but that’s it.

Personally, I would recommend Microsoft other IDE tool, Visual Studio. The same syntax highlighting, and autocomplete functions are readily available, it supports multiple languages, and has a community list of add-ons.

to0c68u

VS Code Syntax Highlighting

Benefits of using Visual Studio Code over ISE:

  • If you decide PowerShell is not for you, change your palette language!
  • Heaps of useful add-ons;
  • Open Source;
  • Fantastic Syntax Highlighting and auto-complete and;
  • Because it’s just better.

 

Using Variables

Variables are the second most powerful “function” (no pun(s) intended) in PowerShell, in my opinion. A variable is a string of data defined in a script that can be referenced later, to make the code shorter, cleaner and more consistent.

A variable can take a complex command, and make it easier to reference down the script. In the following example, I have set 4 variables for commands I wish to use:

$Name = "$env:USERNAME"
$PC = "hostname" 
$Date= "(Get-Date).ToString('dd-MM-yyyy')"
$Time = Get-Date -Format HH-mm-ss

To set a variable, you use the following Syntax:

$Name of the variable = "action to perform"

Which can be translated:

$YourName = Read-Host "What is your name"
Greetings, "$YourName"

Always remember to call a variable using the “$” symbol, and keep it in a quote for clean code.

Variables allow you to replicate a complex command easily, multiple times throughout a script. Editing the function of the variable is reflected each time the script calls the variable. Without variables, code would be a lot messier and could be much harder to debug – a wrong comma in a line incorrectly copied could break the entire script.

Some useful examples are:

Learning how to implement variables allows for scripts that are:

  • Smaller in size;
  • Smaller in code;
  • Generally more robust;
  • Easier to debug;
  • Generally easier to read (if shared)

Using Functions

Functions are perhaps the most useful feature of PowerShell. PowerShell functions, similar to variables, allow you to perform complex command(s), and reference them by a function. The syntax being:

function "name"() {
command 1
command 2
etc
}
name()
  • “name”() is the name of set function;
  • {} are the open and close of the function, placed at beginning and end and;
  • name() actually executes the function; it does not need to be called straight after the function.

Functions support variables that can be predefined in the PowerShell script. In the following example, the function “shutdownalldomainpcs()” is using 4 variables to execute a command:

$H = Read-Host "What is the IP Address of your Domain Controller?" 
$nH = "\\*" 
$-u = Read-Host "What's your domain admin username?" 
$-p = Read-Host "Enter Password"-AsSecureString 
$command = "psexec "$nH" "$-u" "$-p" shutdown -f -r -t 0" 


function shutdownalldomainpcs(){ 
psexec "-H" "$-u" "$-p" "command" 
}
shutdownalldomainpcs

Yes, there may be syntax errors or the command might not even work, I am simply demonstrating. Should totally try with domain admin rights however.

You can read a little more on variables and functions from Microsoft here:

function test ($x, $y) 
 {
 $x * $y 
 }

Enough functions and variables, let’s nest functions! Yeah, you heard me. Functions calling functions!

A simple example:

function 1() {
Write 1
}

function 2() {
Write 2
}

function 3() {
1()
2()
}

3()

The third function executes Function 1 and 2. Handy little trick to allow you to perform multiple steps.

In the following example, I set multiple variables, and then use a “IF” switch to see if a directory is made, and write data to it:

test

Again pure example, code could not work 😉

Some useful links if you are interested:

 

Want to edit this post? Want to post your own content?

I am hoping for some additional writers on this blog. If you want to contribute, please use the comment function, and I will be in touch.