Hosts management tool for linux and windows

hostseditor.ps1

<#
    Hosts file editor: 🄯2020 Aaron Bockelie
    Host Editor works on linux and windows, since my default environment is pscore on linux.
    The fastest way to use this is copy-pasta the script into a ps1 file and dot source it in your session.

    Get-HostEntries: Lists the host entries as objects
    Remove-HostEntry: Removes a host entry by hostname or line number (use Get-HostEntries to get the line numbers)
    Add-HostEntry: Appends a host entry to hosts

    Notes:
    Use -confirm to actually perform the action, otherwise proposed changes are just listed to screen.
    
    Script is OS aware. It will look for hosts in /etc/hosts on a unix platform, and $windir/system32/drivers/etc/hosts on a windows platform.
    
    On liunx, you'll need to "sudo pwsh" and dot source it from there to make changes.
#>

function Locate-HostsFile
{
    switch ($PSVersionTable.Platform) {
        Unix {gci "/etc/hosts"}
        Win32NT {gci (Join-Path -Path $env:WINDIR -ChildPath "system32/drivers/etc/hosts")}
    }
}

function Get-HostEntries
{
    $hostsFile = Get-Content (Locate-HostsFile).FullName
    $entries = [System.Collections.ArrayList]@()
    $i=0
    do {
        if (!$hostsFile[$i].StartsWith("#"))
        {
            if ($hostsFile[$i]) {
                $hostsEntry = $null
                $hostsEntry = [PSCustomObject]@{
                    "Line"=$i;
                    "Name"=($hostsFile[$i] -Split "\s+")[1];
                    "Address"=($hostsFile[$i] -Split "\s+")[0]
                }
                $entries.Add($HostsEntry) | Out-Null
            }
            
        }
        $i++
    }
    until ($i -eq $hostsFile.Length)
    $entries
}

function Remove-HostEntry
{
    [CmdletBinding(DefaultParameterSetName='HostName')]
    param (
        [int][Parameter(ParameterSetName='Line', Position=0)]$Line,
        [string][Parameter(ParameterSetName='Hostname', Position=0)]$Hostname,
        [switch]$confirm
    )
    $hostsFile = Get-Content (Locate-HostsFile).FullName
    $newHostsFile = @()
    $hostEntries = Get-HostEntries
    if ($hostname) {
        $lineItem = ($hostEntries | ?{$_.Name -eq $hostname})
        if ($lineItem.Count -gt 1) {
            #There's probably a better way to manage the multime named hosts corner case
            #usually this is for round robin hosts lookup and should be done in DNS not in a hosts file
            #it would be fairly easy to make this remove all entries matching this name, though
            Throw "Ambiguous host entry (returned more than one match). Try removing by line number."
            $lineItem = $lineItem[0]
        }
    }
    if ($Line) {
        $lineItem = ($hostEntries | ?{$_.Line -eq $Line})
    }

    $i = 0
    if ($confirm) {
        do {
            if ($i -ne $lineItem.Line) {
                $newHostsFile += $hostsFile[$i]
            }
            $i++
        } until ($i -eq $hostsFile.Length)
        $newHostsFile | Out-File (Locate-HostsFile).FullName
    }
    else {
        Write-Warning "Hosts file not updated. Use -Confirm to perform action. Proposed changes below."
        do {
            if ($i -ne $lineItem.Line) {
                ("       " + ('{0:d3}' -f $i) + " @ " + $hostsFile[$i])
            }
            else {
                (('{0:d3}' -f $i) + "        - " + $hostsFile[$i])
            }
            $i++
        } until ($i -eq $hostsFile.Length)
        return
    }
}

function Add-HostEntry
{
    param (
        $HostName,
        $Address,
        [switch]$Confirm
    )
    switch ($PSVersionTable.Platform) {
        Unix {$Delimiter = "`t"}
        Win32NT {$Delimiter = "`t`t"}
    }
    $hostsFile = Get-Content (Locate-HostsFile).FullName
    $NewHostEntry = ($Address + $Delimiter + $Hostname)
    $i = 0

    if ($confirm) {
        Add-Content -Path (Locate-HostsFile).FullName -Value $NewHostEntry
    }
    else {
        Write-Warning "Hosts file not updated. Use -Confirm to perform action. Proposed changes below."
        do {
                ("       " + ('{0:d3}' -f $i) + " @ " + $hostsFile[$i])
                $i++  
        } until ($i -eq $hostsFile.Length)
        (('{0:d3}' -f $i) + "        + " + $NewHostEntry)
        return
    }
}