Press F1 to view the currently typed command help online

PutInYourProfile.ps1

using namespace System.Management.Automation
using namespace System.Management.Automation.Language
#requires -version 5

# Stolen and modified from https://github.com/PowerShell/PSReadLine/blob/master/PSReadLine/SamplePSReadLineProfile.ps1
# F1 for help on the command line - naturally
Set-PSReadLineKeyHandler -Key F1 `
  -BriefDescription CommandHelp `
  -LongDescription 'Open the help window for the current command' `
  -ScriptBlock {
  param($key, $arg)

  $ast = $null
  $tokens = $null
  $errors = $null
  $cursor = $null
  [Microsoft.PowerShell.PSConsoleReadLine]::GetBufferState([ref]$ast, [ref]$tokens, [ref]$errors, [ref]$cursor)

  $commandAst = $ast.FindAll( {
      $node = $args[0]
      $node -is [CommandAst] -and
      $node.Extent.StartOffset -le $cursor -and
      $node.Extent.EndOffset -ge $cursor
    }, $true) | Select-Object -Last 1

  if ($commandAst -ne $null) {
    $commandName = $commandAst.GetCommandName()
    if ($commandName -ne $null) {
      $command = $ExecutionContext.InvokeCommand.GetCommand($commandName, 'All')
      if ($command -is [Management.Automation.AliasInfo]) {
        $commandName = $command.ResolvedCommandName
      }

      if ($commandName -ne $null) {
        #First try online
        try {
          Get-Help $commandName -Online -ErrorAction Stop
        } catch [InvalidOperationException] {
          if ($PSItem -notmatch 'The online version of this Help topic cannot be displayed') { throw }
          Get-Help $CommandName -ShowWindow
        }
      }
    }
  }
}