PowerShell Interview Questions

Introduction to PowerShell Interview Questions and Answers

PowerShell is a task automation software and configuration management framework created by famous software company Microsoft. It consists of a command-line shell and also an associated scripting language. Earlier, PowerShell was a Windows component only, and it was known as Windows PowerShell, but later it was made open-source. After that, it also introduced PowerShell Core. Now PowerShell is a cross-platform framework. It was built on the .NET Framework and the latest version is built on .NET Core. PowerShell provides features such as full access to COM and WMI, which enables administrators to perform many administrative tasks on both local as well as remote Windows systems. PowerShell also provides a hosting API which can be used by the PowerShell runtime to be embedded inside with other applications. These applications then take maximum benefits of PowerShell functionality to implement certain operations which may include graphical interface etc.

Now, if you are looking for a job which is related to PowerShell then you need to prepare for the 2019 PowerShell Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important PowerShell Interview Questions and Answers which will help you get success in your interview.

In this 2019 PowerShell Interview Questions article, we shall present 10 most important and frequently used PowerShell interview questions. These interview questions are divided into two parts are as follows:

Part 1 – PowerShell Interview Questions (Basic)

This first part covers basic PowerShell Interview Questions and Answers.

Q1. Explain what do you understand by PowerShell?

Answer:

• PowerShell is a shell designed keeping in mind the need of system administrators.
• It is open Source and Platform Independent i.e. works for Windows/Linux/Mac.
• It is object-oriented and not text-based.
• It is built on a .NET framework.
• It has an Interactive prompt and also a scripting environment.

Q2. Explain Execution Policies and types of Execution Policy?

Answer:
This is the common PowerShell Interview Questions asked in an interview. There are 6 types of execution policies in PowerShell. These are:-

• Restricted: This is the default type. Under this, PowerShell will not run any script including PowerShell profiles too.
• RemoteSigned: PowerShell will only run any script that is created locally. Any script that has been coming from the Internet should be digitally signed with a signing certificate code and is trusted by the computer.
• AllSigned: PowerShell will only run any script that has been digitally signed using a trusted code signing certificate.
• Unrestricted: PowerShell will run any script. If the script comes from an untrusted source, users are prompted once to execute it.
• Bypass: This policy will run any script without any question or prompt.
• Undefined: There is no execution policy set for this in the current scope.

Q3. What is the PowerShell order in which execution policy is evaluated?

Answer:
Windows PowerShell has execution policies in the following order of precedence –

• Group Policy: Example is Computer Configuration.
• Group Policy: Example is User Configuration.
• Execution Policy: Such as Process (or PowerShell.exe -Execution Policy) – which is the CURRENT SCOPE.
• Execution Policy: Such as Current User – Which is SAVED in the HKCU registry.
• Execution Policy: Such as Local Machine – which is SAVED in the HKLM registry.

Let us move to the next PowerShell Interview Questions.

Q4. Explain the difference between CIM vs WMI.

Answer:

Old WMI	New WMI	CIM
It has full form of Windows Management Instrumentation.	It has full form of Windows Management Instrumentation.	It has a full form of the Common Information Model.
Old WMI is actually Microsoft’s initial implementation of CIM.	New WMI was released along with WMF v3 in 2012 and it was compliant to new CIM standards.	It is Vendor-neutral and industry standard way of representation of management information.
It is Developed by Microsoft.	It is Developed by Microsoft as well.	It is Developed by another company called the DMTF.
It is there Since PowerShell v1.	It is Introduced in PowerShell v3.	Not available.
It used DCOM or Distributed COM) and RPCs Remote Procedure Calls.	It Uses WSMan and no more DCOM errors are possible with this.	It Uses WSMan which is a standard developed by DMTF.
It works for Windows only.	This also works for Windows only.	It can work in any Any platform.
It has RPC port- 135 for use.	It has WSMan Port – 5985 (HTTP) and 5986(HTTPS) for use.	It uses WSMan Port – 5985 (HTTP) and 5986(HTTPS) for its purpose.

Q5. Further, differentiate between the concept of WMI between Old and new ideas.

Answer:
Old WMI

• Uses old-style native code providers and a repository for itself.
• Available only on Windows as mentioned.
• It has been more or less deprecated which means it’s is not focused on further improvement or development.

New WMI

• Supports old-style native code providers and a repository, as well as new-style MI providers as discussed.
• Available only on Windows as mentioned.
• This is the way forward. It has an essentially stateless relationship with the remote machine.

Part 2 – PowerShell Interview Questions (Advanced)

Let us now have a look at the advanced PowerShell Interview Questions and Answers.

Q6. Differentiate between OMI and CIM.

Answer:
OMI

• It uses WS-MAN where OMI code includes the protocol stack od WS-MAN. It supports only new-style MI providers.
• It is available on any implementing platform. If something can talk to OMI, it will be able to talk to NEW WMI as well.

CIM

• It defines the standard. It is created by DMTF.
• In this case, early versions were implemented as OLD WMI actually by Microsoft, but the newest version implemented both in NEW WMI and OMI by Microsoft as well as others.

Q7. Provide distinction among WinRM and WSMan and DCOM.

Answer:
This is the most popular PowerShell Interview Questions asked in an interview.

WSMan

• WS-Management abbreviated as WSMAN or Web Services-Management is basically a Distributed Management task force.
• It is an open standard which defines a SOAP-based (full form Simple Object Access Protocol) protocol for the management of its servers, devices, applications and also various Web services.

WinRM

• WinRM is a feature which came from Windows Vista and it allows administrators to remotely run management scripts.
• It can handle remote connections using the WS-Management Protocol.

DCOM

• DCOM means Distributed COM.
• It is used to connect LIVE objects which are on the remote machine.
• The RPC protocol that it uses was designed for continuous back-and-forth messaging.
• It is network and memory inefficient.

Q8. What do you understand by Automatic variables?

Answer:

• Automatic variables are those that describe variables that store state information for PowerShell.
• These variables are mainly created and maintained by PowerShell itself.

Some of the very common Automatic Variables are as below:

• $$ – This variable contains the last token available in the last line received by the session.
• $? – This may contain the execution status of the last operation. Its value is TRUE if the last operation succeeded and FALSE if it failed.
• $^ – It may contain the first token of the last line received by the session.

Let us move to the next PowerShell Interview Questions.

Q9. What is $Error and $ForEach variable?

Answer:
$Error – This variable contains an array of error objects which represents the most recent errors. The most recent error is the first error in the array.

$ForEach – This variable contains the enumerator (should not be confused with the resulting values) of a for each loop. Properties and methods of enumerators can be used on the value of the $ForEach variable. This kind of variable exists only while the for each loop is in running state, and it is deleted once the loop is completed.

Q10. What are $Home and $PID?

Answer:
$Home – This variable contains the complete path of the user’s home directory. This variable can be considered as the equivalent of the %homedrive%%homepath% environment variables in windows such as C:\Users<UserName.

$PID – This may contain the process identifier of the process which is hosting the current Windows PowerShell session.

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