Windows PowerShell Cheat Sheet

Overview

This Windows PowerShell cheat sheet helps you start quickly with the bash-equivalent tool on the Windows environment. I was a fan of Linux’s terminal and found Windows Powershell so “lame”. I was so wrong. Windows Powershell is mighty too.

Let’s find out what it can do.

Basic Windows PowerShell Commands

Here are the most common commands you do on a daily basis with any terminal.

Create new file

On Linux, you can use the touch command, on Windows Powershell, you use new-item:

Create a new file in windows powershell
Create a new file in windows powershell

Write content to file

You can write content to files similar to what you do on Linux. The following command writes content to the file and overwrites all existing content:

"Some file content" > .\first-file.txt
Write content to file using powershell
Write content to file using PowerShell

If you want to append, instead of overwrite, you can use >>

"Append a new line" >> .\first-file.txt
Append text to file instead of overwriting
Append text to file instead of overwriting

Read content from a file

As you can see from the screenshots above, you can read content from a file in Powershell using get-content.

Variables

Let’s get a bit more advanced. You can create variables in Windows Powershell quite easily

# Declare a variable
$name = "Luis"

# print the variable
$name

# Doing arithmetic
$sum = 1+2

$job = "developer"

# String concatenation
$name + " is a " + $job
Basic operations on variables
Basic operations on variables

Comparison in Windows Powershell

You can do comparisons (equals, greater than, less than, not equals in Powershell quite easily)

Basic comparison

# compare numbers

# equal comparison
1 -eq 2 # False
 
"a" -eq "a" # True

"a" -eq "b" # False

# not equal comparison
1 -ne 2 # True

# less than comparison
1 -lt 2 # True

# greater than comparison
1 -gt 2 # False

Basic comparisons in Windows PowerShell
Basic comparisons in Windows Powershell

String comparison

Besides supporting basic string comparisons, as shown above, Powershell also supports more powerful comparisons for strings:

By default, when doing a comparison between strings, PowerShell doesn’t take casing into account. Thus, you will see “Orange” equals “ORANGE”

Case insensitive comparison

Case sensitive comparison

If you want to also check case-sensitive equals, use -ceq instead of eq

Case sensitive string comparison
Case-sensitive string comparison

Wildcard comparison

There are times you want to do wildcard (not regex, if you want to use regex, use -match) with string. For example, you want to check if “Orange” starts with “Or”.

You will want to use the -like operator

"Orange" -like "Or*"

 "Orange" -like "*an*"

"Orange" -like "*g"
Wildcard matching in Powershell
Wildcard matching in Powershell

As you can see, the * character represents 0 or many characters.

If you want to represent exactly one character, use the question mark(?) instead:

Exactly one character matching with ?
Exactly one character matching with ?

Regex matching with -match

You can use -match to do regex matching in Windows Powershell.

Regex matching with -match
Regex matching with -match

Alias

If you are familiar with commands like ls, touch, cat… in Linux, you can use such commands on Windows Powershell using an alias.

To create an alias use set-alias:

Creating an alias using set-alias
Creating an alias using set-alias

In the screenshot above, I created an alias for new-item and named it touch (similar to that of Linux).

Then, I could use the touch command to create a new file.

Objects

Almost anything in Powershell is an object. If you come from object oriented programming language, you know that object has method and properties (members).

To get all members of an object in Powershell, use get-member after the pipe character.

For example, to get all members of a certain string:

"some string" | get-member
List of members of the string type
Members of the string type

As you can see, there are a lot of operations you can do on a string. Let’s try some common methods:

Some common string operations
Some common string operations

Even a number, which in other programming is considered “primitive” is an object in Powershell

A number is also an object in Powershell
A number is also an object in Powershell

Filter a list

Imagine you do a dir or ls in a directory that has many files and you want to filter out files that don’t begin with the letter s.

 ls | where{($_.Name -like "s*")}

You can filter results in Powershell using where

Filter list of directory using where
Filter list of directory using where

You can use multiple where conditions, not just one. For example, in addition to having a name that begins with the letter s, you also want to get the files that have a length greater than 3000:

 ls | where{($_.Name -like "s*") -and ($_.Length -gt 3000) }
Multiple filter conditions using -where, -and
Multiple filter conditions using -where, -and

Array

It’s very simple to create an array in Powershell

$animals = @("Dog", "Cat", "Lion")
$animals
Create an array in Powershell
Create an array in Powershell

In Powershell, you can have multiple types within an array. For example, you can have both string and number in one array:

Multiple data types in an array

And you can do filter in the mixed-type array without any issues:

Filter on mixed-type array

You can add two arrays together to form a bigger array (duplicate elements are not removed, as expected).

Array in Powershell is zero-based:

Operations on powershell array
Operations on powershell array

HashMap/HashTable

Powershell supports HashMap data type. You can create a HashMap as simple as creating an array:

$carPrices= @{"Lexus" = 3000; "Ford Explorer" = 2700}
Declare a HashMap and get elements by key
Declare a HashMap and get elements by key

As you can see from the example, you can only get the value by entering the exact key, wildcard querying is not supported.

Sorting

Sorting is a very useful tool in any terminal application.

Powershell has extensive support for sorting.

Sorting an array

Let’s create an array of animals and try the sorting function on that array:

$houseAnimals = @("Cat", "Dog", "Cow", "Hen", "Lice", "Mosquito", "Snake", "Buffalo")
Sorting in powershell by default by alphabet, ascending
Sorting in powershell by default by alphabet, ascending

As you can see, by passing the sort function after the pipe, the list of animals appeared in alphabetic order.

If you want to change the order to descending, use the -desc option:

Sort in descending order
Sort in descending order

Sorting by attributes

Take the dir/ls command for example. The result of these commands is a list of files in the current directory.

By using sort, you can sort the output by various attribute such as file’s name, file’s size, last write…

Sort list of files by name
Sort by descending order
Sort by file size, descending order
Sort by file size, descending order

Conclusion

This post covers the basic commands of Windows Powershell. By no means it’s a comprehensive introduction to all features of Powershell. However, I think it’s enough for you to see the power of this shell. In my opinion, it can do many great things, as great as bash on Linux.


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