You can use the following methods in PowerShell to remove the last character from a string:
Method 1: Remove Last Character from String
$my_string = $my_string -replace ".$"
This particular example removes the last character in the string variable named $my_string.
Method 2: Remove Last N Characters from String
$my_string = $my_string -replace ".{3}$"
This particular example removes the last 3 characters in the string variable named $my_string.
Note that both of these methods use -replace along with .$ to match the last character in a string and replace it with nothing, which allows us to remove the last character in the string.
The following examples show how to use each method in practice.
Example 1: Remove Last Character from String in PowerShell
We can use the following syntax to remove the last character of a string variable in PowerShell:
$my_string = "The Mavs are my favorite team"
$my_string = $my_string -replace ".$"
The following example shows how to use this syntax in practice:

Notice that the last character in the string has been removed.
Example 2: Remove Last N Characters from String in PowerShell
We can use the following syntax to remove the last three characters of a string variable in PowerShell:
$my_string = "The Mavs are my favorite team"
$my_string = $my_string -replace ".{3}$"
The following example shows how to use this syntax in practice:

Notice that the last three characters in the string have been removed.
Note: Feel free to replace the 3 in the code with a different number to instead remove a different number of characters from the end of a string.
Related Tutorials
The following tutorials explain how to perform other common tasks in PowerShell:
PowerShell: How to Get Last Item in Array
PowerShell: How to List Files in Directory by Date
PowerShell: How to List All Files in Directory to Text File
