Automatic Variables

Variable	Description
`$$`	Returns the last token in the last line received by the session
`$^`	Returns the first token in the last line received by the session
`$?`	Returns bool if the last command succeeded
`$_`	Alias to `$PSItem`. Returns the current object in the pipeline object. Use in commands that perform an action on every object in the pipeline.
`$Error`	Returns an array of error objects of the most recent errors
`$HOME`	Returns the full path of the user’s home directory (same as $env:USERPROFILE)
`$Host`	An object that represents the current host application for PowerShell
`$isCoreCLR`
`$isLinux`
`$isMacOS`
`$isWindows`
`$LASTEXITCODE`	Returns the exit code of the last native program or PowerShell script ran
`$PROFILE`	The full path of the posh profile for the current user and current host application
`$PSHOME`	The full path of the installation directory for posh
`$PWD`	The current working directory
`$StackTrace`	The stack trace for the most recent error

Chaining Commands

Run cmd2 only if cmd1 succeeds: cmd1 && cmd2
Run cmd2 only if cmd1 fails: cmd1 || cmd2
Run cmd1 and cmd2 regardless of cmd1’s result: cmd1; cmd2

Environment Variables

Get:

$Env:variable-name

Set:

$Env:variable-name = "new-value"  
$Env:variable-name += "new-value-to-append"

Persist:

[Environment]::SetEnvironmentVariable('key', 'value', 'scope') # scope = machine or user

Set environment variables

Set an environment variable for this session only: set key="value"
Set an environment variable that persists: setx key="value"
Set the environment variable in system intead of user: setx /M key="value"
Set an environment variable that has a hierarchical key: set level1:level2="value"

The : separator is not recognized on all platforms. Use __ instead: set level1__level2="value"

Files & Directories

Cat Clipboard to File

Get-Clipboard | Out-File filename

Copy Files / Directories

copy /srcdir/subdir /dstdir/newsubdir -Recurse # copy /srcdir/subdir and all of its files and subdirectories to /dstdir/newsubdir and create it if it doesn't exist

CWD

Get-Location

Find

gci -Path <starting-path> `
    -Include <glob> `
    -Directory <# if only directories should be returned, not files #>`
    -File <# if only files should be returned, not directories #>`
    -Exclude <glob>
    -ErrorAction SilentlyContinue
    -Recurse -Force

“grep”

Get-ChildItem -Path ./*.<EXT> -Recurse | Select-String 
  -Pattern "<REGEX>" <# The pattern to match #>`
  -Context n,m <# Add n lines before and m lines after the match; matches are denoted with > #>
  -Raw # Don't output file names

Pipe to a File

cmd | out-file filename

Pipe to a File and Console

cmd | Tee-Object -File filename

Remove Directory Recursively

ri path -Recurse -Force

Remove File Recursively

Get-ChildItem  -Include .csv -Recurse | Remove-Item

“tail”

Get-Content filename -Tail n

“tail -f”

Get-Content path -Tail 1 -Wait

“touch”

ni filename

Write to a File

Set-Content -Path ./path/to/file.txt -Value 'Hello, World'

Write to a Specific Line in a File

$fileContent = Get-Content $filePath
$fileContent[$lineNumber-1] += $textToAdd
$fileContent | Set-Content $filePath

History

get-history # Stored in `%userprofile%\AppData\Roaming\Microsoft\Windows\PowerShell\PSReadline`

PowerShell version

$PSVersionTable

Profiles

Locations
AllUsersAllHosts, AllUsersCurrentHost, CurrentUserAllHosts, CurrentUserCurrentHost

Set a Profile

notepad $Profile.Location

System Folders

[environment]::getfolderpath("system-folder-name")

Windows Services

Get-Services [-DisplayName "glob"]