PowerShell is a cross-platform, object-oriented scripting language and command-line shell created by Microsoft. It is designed for system administrators and developers to automate tasks and manage configurations across Windows, Linux, and macOS.
PowerShell variables are prefixed with a $ symbol and can store a variety of data types, including strings, integers, arrays, and objects.
# String variable
$name = "Alice"
# Integer variable
$age = 30
# Array variable
$numbers = @(1, 2, 3, 4, 5)
# Object variable
$person = @{
Name = "Bob"
Age = 40
}
PowerShell has a large number of built-in cmdlets (pronounced “command-lets”) for common tasks such as string manipulation, file I/O, and process management. Cmdlets are called using a verb-noun syntax.
# String manipulation
$name = "Alice"
$length = $name.Length # Returns 5
# File I/O
Get-Content -Path "input.txt"
# Process management
Get-Process | Where-Object {$_.Name -eq "notepad"}
PowerShell has several types of loops, including for, foreach, while, and do-while. The for and foreach loops are used to iterate over arrays or lists, while the while and do-while loops are used to repeat a block of code while a condition is true or false, respectively.
# For loop
for ($i = 0; $i -lt 10; $i++) {
Write-Output $i
}
# Foreach loop
$numbers = @(1, 2, 3, 4, 5)
foreach ($num in $numbers) {
Write-Output $num
}
# While loop
$i = 0
while ($i -lt 10) {
Write-Output $i
$i++
}
# Do-while loop
$i = 0
do {
Write-Output $i
$i++
} while ($i -lt 10)
PowerShell has several conditional statements, including if, elseif, else, and switch. These statements are used to control the flow of a program based on certain conditions.
# If statement
$age = 30
if ($age -ge 18) {
Write-Output "You are an adult"
}
# If-else statement
$age = 15
if ($age -ge 18) {
Write-Output "You are an adult"
} else {
Write-Output "You are a minor"
}
# If-elseif-else statement
$age = 25
if ($age -lt 18) {
Write-Output "You are a minor"
} elseif ($age -lt 65) {
Write-Output "You are an adult"
} else {
Write-Output "You are a senior"
}
# Switch statement
$fruit = "apple"
switch ($fruit) {
"apple" {
Write-Output "It's an apple"
}
"banana" {
Write-Output "It's a banana"
}
default {
Write-Output "It's something else"
}
}
PowerShell provides several cmdlets for manipulating files, including Get-Content, Set-Content, Rename-Item, and Remove-Item.
# Read file contents
Get-Content -Path "input.txt"
# Write to file
Set-Content -Path "output.txt" -Value "Hello, world!"
# Rename file
Rename-Item -Path "input.txt" -NewName "input.old"
# Remove file
Remove-Item -Path "output.txt"