Unix style which command should be built in as an alias. #2885

wpostma · 2016-12-14T20:40:23Z

My most frequent annoyance on Powershell is typing in a Unix command that everybody knows and unlike ls, or echo or cd, it doesn't just work. The one I find myself missing most often is which, which I define on my own system as:

function which($name)
{
    Get-Command -Name $name | Select-Object -ExpandProperty Definition
}

That makes me happy on my computer and sad on everyone else's computer where I can't just go install my powershell profile, so I have to go copy and paste that from somewhere into my session, just so I can save myself typing the horrific long forms in over and over. It seems to me that which is so darn useful that the above alias should just exist by default in powershell.

Searching for a binary in the path is a frequent task, and the above long-form command that my alias saves you from typing is among the most egregious examples of a COBOL-like verbosity in PowerShell that I find completely distasteful. I can't remember all that crap. which foo and you're done.

Now that powershell is cross platform, and a very useful tool on any system where it can run, including Unix systems, it seems that which should make the trip. which defined as above, works for aliases, and, functions, and binary tools on the path. That makes it an essential tool in your toolbox, and should be covered by the "obviously, should just work" criteria.

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@wpostma

credit to @wpostma from PowerShell/PowerShell#2885

joeyaiello · 2016-12-14T22:07:33Z

I totally understand the appeal (and I'm currently copying that into my own personal profile). Unfortunately, this is dangerous for reasons outlined in #1901 and #929. tl;dr: especially in non-Windows scenarios, shells shouldn't plaster over native binaries on the box because users expect the binaries that they're used to (e.g. ls -la or rm -rf should just work on Linux boxes).

In this particular instance, unless we implement all the switches available to GNU which, we're going to get in trouble with people on the *nix side.

That being side, I believe we should eventually do some kind of module that gives PowerShell power users aliases like this.

wpostma · 2016-12-15T19:39:54Z

Ah. Yes, I can see the need to not hide "which" if it's already in the path. For such a purpose, I think then a new Powershell syntax needs to be defined that allows for polyfills (that is, do not replace which if it's in the path).

Current Powershell semantics make it impossible for me to write this and have my profile automatically create a function if there is NO command found matching the name which:

try  { Get-Command -Name which 
 } 
catch <#CommandNotFoundExeception#> { function which($name)
  {
     Get-Command -Name $name | Select-Object -ExpandProperty Definition
  }
 }

DerpMcDerp · 2016-12-16T03:58:50Z

The "see" command is more feature rich (and shorter to type too):

http://poshcode.org/5164

wpostma · 2016-12-16T12:06:02Z

How is that command different than the built in Get-Command that my which function example has? I didn't see how it's called see from that code either?

DerpMcDerp · 2016-12-17T00:13:26Z

I didn't see how it's called see from that code either?

There is an alias up top:

New-Alias see Get-CommandDefinition

How is that command different than the built in Get-Command that my which function example has?

see unrolls aliases automatically and tells you the name of the cmdlets and dlls they're in, e.g.

<#PS#> New-Alias foo bar
<#PS#> New-Alias bar ls

<#PS#> which foo
bar
<#PS#> which Get-ChildItem
Get-ChildItem [[-Path] <string[]>] [[-Filter] <string>] [-Include <
8000
string[]>] [-Exclude <string[]>] [-Recurse] [-Depth <uint32>] [-Force] [-Name] [-UseTransaction] [-Attributes <FlagsExpression[FileAttributes]>] [-Directory] [-File] [-Hidden] [-ReadOnly] [-System] [<CommonParameters>]

Get-ChildItem [[-Filter] <string>] -LiteralPath <string[]> [-Include <string[]>] [-Exclude <string[]>] [-Recurse] [-Depth <uint32>] [-Force] [-Name] [-UseTransaction] [-Attributes <FlagsExpression[FileAttributes]>] [-Directory] [-File] [-Hidden] [-ReadOnly] [-System] [<CommonParameters>]

<#PS#> see foo
#A: foo -> bar
#A: bar -> ls
#A: ls -> Get-ChildItem
# Microsoft.PowerShell.Commands.Management.dll
#   Microsoft.PowerShell.Commands.GetChildItemCommand

Get-ChildItem [[-Path] <string[]>] [[-Filter] <string>] [-Include <string[]>] [-Exclude <string[]>] [-Recurse] [-Depth <uint32>] [-Force] [-Name] [-UseTransaction] [<CommonParameters>]

Get-ChildItem [[-Filter] <string>] -LiteralPath <string[]> [-Include <string[]>] [-Exclude <string[]>] [-Recurse] [-Depth <uint32>] [-Force] [-Name] [-UseTransaction] [<CommonParameters>]

see can tell you if the function is in a module, e.g.

<#PS#> which PSConsoleHostReadline
    Microsoft.PowerShell.Core\Set-StrictMode -Off
    [Microsoft.PowerShell.PSConsoleReadLine]::ReadLine($host.Runspace, $ExecutionContext)

<#PS#> see PSConsoleHostReadline
#F: PSReadline\PSConsoleHostReadline

    Microsoft.PowerShell.Core\Set-StrictMode -Off
    [Microsoft.PowerShell.PSConsoleReadLine]::ReadLine($host.Runspace, $ExecutionContext)

iSazonov · 2017-10-08T08:32:33Z

It is dup #1975

@wpostma

credit to @wpostma from PowerShell/PowerShell#2885

@wpostma

credit to @wpostma from PowerShell/PowerShell#2885

joeyaiello added the WG-DevEx-Portability authoring cross-platform or cross-architecture modules, cmdlets, and scripts label Dec 14, 2016

joeyaiello added a commit to joeyaiello/joeyaiello that referenced this issue Dec 14, 2016

add which function

f4193bc

credit to @wpostma from PowerShell/PowerShell#2885

mklement0 mentioned this issue Jul 15, 2017

ignore #4263

Closed

iSazonov closed this as completed Oct 8, 2017

iSazonov added the Resolution-Duplicate The issue is a duplicate. label Oct 8, 2017

joeyaiello added a commit to joeyaiello/joeyaiello that referenced this issue May 28, 2018

add which function

88656ea

credit to @wpostma from PowerShell/PowerShell#2885

joeyaiello added a commit to joeyaiello/joeyaiello that referenced this issue Dec 19, 2021

add which function

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credit to @wpostma from PowerShell/PowerShell#2885

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Unix style which command should be built in as an alias. #2885

Unix style which command should be built in as an alias. #2885

Unix style which command should be built in as an alias. #2885

Unix style which command should be built in as an alias. #2885

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