In part I of Put the Alias Description Property to Work, I showed and explained how to add a description property to each of my personal, profile script-created aliases. This allowed me to use a basic function, that filtered the Get-Alias results to return only my aliases. In this post, we will take this one step further and we will add descriptions to the built-in aliases in PowerShell. If you remember, we determined that most of the built-in aliases do not include a source property. Therefore, sorting or filtering on that property is of little value.
The source property is not a settable property, meaning that no matter how hard I try, I cannot edit it. The Description property, as we learned, is open for me to make changes. This is also true with built-in aliases and not just the aliases I create. Here is what we are going to do. All the aliases resolve to a command, and all but four of those commands have a source property. We are going to acquire a command’s source and set it as the description of its alias. This might make more sense with some examples, so let’s start there.
But before we do, let’s look at the default properties returned by Get-Alias.
Get-Alias | Get-Random
CommandType Name Version Source
----------- ---- ------- ------
Alias pwd -> Get-Location
Get-Alias returns CommandType, Name, Version, and Source. Kind of. Name is really a property called DisplayName. It may be better to know that now. In the first, real example, we are also going to use Get-Random to randomly select an alias for us. Then, we will return its ResolvedCommandName, DisplayName, Description, and Options properties.
$Alias = Get-Alias | Get-Random
Get-Alias -Name $Alias |
Select-Object ResolvedCommandName,DisplayName,Description,Options
ResolvedCommandName DisplayName Description Options
------------------- ----------- ----------- -------
Connect-PSSession cnsn -> Connect-PSSession ReadOnly
Notice that currently, its Description property is blank. In the next example, we will use the value stored in $Alias and run it through a ForEach-Object loop. Take a look at the PowerShell now, and I will do that recently experimented with, line-by-line explanation further below.
Get-Alias -Name $Alias | ForEach-Object {
if ($_.Description -eq '') {
$Params = @{
Name = $_.Name
Value = $_.ResolvedCommandName
Description = if ((Get-Command -Name $_.ResolvedCommandName).Source) {
((Get-Command -Name $_.ResolvedCommandName).Source)
} else {'None'}
Option = $_.Options
Force = $true
}
Set-Alias @Params -Verbose
}
}
VERBOSE: Performing the operation "Set Alias" on target "Name: cnsn Value: Connect-PSSession".
Line 1: Pipe our single alias into a ForEach-Object loop.
Line 2: Continue into an if construct if the alias’ description is empty. If it is not, we would move on to the next alias if there were more than just one.
Line 3: Create a hash table and store it in the $Params variable.
Line 4, 5: Add the name and the resolved command name into the Name and Value keys, respectively.
Line 6 – 8: Add a description to the Description key based on whether or not there is a source. If there is a source, add it, if there is not a source add the string None.
Line 9, 10: Add the options and $true value into the Option and Force keys, respectively.
Line 12: Invoke the Set-Alias command, splatting the $Params hash table as parameters and associated parameter values.
Let’s rerun the command we did just a minute ago.
Get-Alias -Name $Alias |
Select-Object ResolvedCommandName,DisplayName,Description,Options
ResolvedCommandName DisplayName Description Options
------------------- ----------- ----------- -------
Connect-PSSession cnsn -> Connect-PSSession Microsoft.PowerShell.Core ReadOnly
We have taken the source of the command Connect-PSSession and placed its value into the description of an alias that resolves to Connect-PSSession. It is not genius, but it is something!
Moving on, the next command pipes out all the known aliases and the values in each of the included properties. I will only include the first ten, as there are almost 150.
Get-Alias |
Select-Object ResolvedCommandName,DisplayName,Description,Options
ResolvedCommandName DisplayName Description Options
------------------- ----------- ----------- -------
Where-Object ? -> Where-Object ReadOnly, AllScope
ForEach-Object % -> ForEach-Object ReadOnly, AllScope
Add-Content ac -> Add-Content ReadOnly
Clear-Host c -> Clear-Host tommymaynard None
Get-Content cat -> Get-Content None
Set-Location cd -> Set-Location AllScope
Set-Location chdir -> Set-Location None
Clear-Content clc -> Clear-Content ReadOnly
Clear-Host clear -> Clear-Host None
Clear-History clhy -> Clear-History ReadOnly
This should look familiar. There are a couple of differences in this code block compared to the one above. One, we are piping in all of the aliases (not just one), and two, there is no Verbose parameter included when the Set-Alias command is invoked. We do not need to output the change made to each alias. Yeah, no thanks.
Get-Alias | ForEach-Object {
if ($_.Description -eq '') {
$Params = @{
Name = $_.Name
Value = $_.ResolvedCommandName
Description = if ((Get-Command -Name $_.ResolvedCommandName).Source) {
((Get-Command -Name $_.ResolvedCommandName).Source)
} else {'None'}
Option = $_.Options
Force = $true
}
Set-Alias @Params
}
}
This is the same command we saw earlier. I have only included the first ten here, as well. Notice the changes made to the Description property for each alias. Now I can easily see which alias goes with which source.
Get-Alias |
Select-Object ResolvedCommandName,DisplayName,Description,Options
ResolvedCommandName DisplayName Description Options
------------------- ----------- ----------- -------
Where-Object ? -> Where-Object Microsoft.PowerShell.Core ReadOnly, AllScope
ForEach-Object % -> ForEach-Object Microsoft.PowerShell.Core ReadOnly, AllScope
Add-Content ac -> Add-Content Microsoft.PowerShell.Management ReadOnly
Clear-Host c -> Clear-Host tommymaynard None
Get-Content cat -> Get-Content Microsoft.PowerShell.Management None
Set-Location cd -> Set-Location Microsoft.PowerShell.Management AllScope
Set-Location chdir -> Set-Location Microsoft.PowerShell.Management None
Clear-Content clc -> Clear-Content Microsoft.PowerShell.Management ReadOnly
Clear-Host clear -> Clear-Host None None
Clear-History clhy -> Clear-History Microsoft.PowerShell.Core ReadOnly
Like all worthy PowerShell code, I am going to wrap this in a function, and for the foreseeable future, copy this into my profile script. There is one change in this version that should be mentioned. The Scope parameter is now being included inside the $Params hash table with the Global value. Like the other parameters and parameters values in this hash table, it will be splatted onto the Set-Alias cmdlet when it is invoked. While the Scope parameter is not required with Get-Alias, it absolutely is with Set-Alias. We want the aliases that exist outside the function to be the ones we modify.
function Set-AliasDescription
Get-Alias | ForEach-Object {
if ($_.Description -eq '') {
$Params = @{
Name = $_.Name
Value = $_.ResolvedCommandName
Description = if ((Get-Command -Name $_.ResolvedCommandName).Source) {
((Get-Command -Name $_.ResolvedCommandName).Source)
} else {'None'}
Option = $_.Options
Force = $true
Scope = 'Global'
}
Set-Alias @Params
}
}
Set-AliasDescription
With the descriptions set, we can filter such as in the next two examples. Remember, the Get-Alias Description property is not displayed by default.
Get-Alias | Where-Object -Property Description -eq 'None'
CommandType Name Version Source
----------- ---- ------- ------
Alias clear -> Clear-Host
Alias cls -> Clear-Host
Alias man -> help
Alias md -> mkdir
Get-Alias | Where-Object -Property Description -like '*core'
CommandType Name Version Source
----------- ---- ------- ------
Alias ? -> Where-Object
Alias % -> ForEach-Object
Alias clhy -> Clear-History
Alias cnsn -> Connect-PSSession
Alias dnsn -> Disconnect-PSSession
Alias etsn -> Enter-PSSession
Alias exsn -> Exit-PSSession
Alias foreach -> ForEach-Object
Alias gcm -> Get-Command
Alias ghy -> Get-History
Alias gjb -> Get-Job
Alias gmo -> Get-Module
Alias gsn -> Get-PSSession
Alias h -> Get-History
Alias history -> Get-History
Alias icm -> Invoke-Command
Alias ihy -> Invoke-History
Alias ipmo -> Import-Module
Alias nmo -> New-Module
Alias nsn -> New-PSSession
Alias oh -> Out-Host
Alias r -> Invoke-History
Alias rcjb -> Receive-Job
Alias rcsn -> Receive-PSSession
Alias rjb -> Remove-Job
Alias rmo -> Remove-Module
Alias rsn -> Remove-PSSession
Alias sajb -> Start-Job
Alias spjb -> Stop-Job
Alias where -> Where-Object
Alias wjb -> Wait-Job
