Getting the first argument passed to the cli

Trying just to write a simple script that would return the SHA256 signature of a file using the file name passed to my ps1 script :

The scriptname is sha256sum.ps1.

The first argument will be any file, example :

sha256sum.ps1 dummy.exe

I tried these inside sha256sum.ps1 :

Get-FileHash -algo SHA256 %1
Get-FileHash -algo SHA256 $1
Get-FileHash -algo SHA256 $args[1]

but none of them worked.

Is there a simple way to do that ?

EDIT : Here is the final version of my script thanks to your help, guys :)

#!/usr/bin/env pwsh
param( $firstArg )

function calcSignature( $filename ) {
    $scriptName = Split-Path -Leaf $PSCommandPath
    switch( $scriptName ) {
        "md5sum.ps1"    { $algo = "MD5";    Break }
        "sha1sum.ps1"   { $algo = "SHA1";   Break }
        "sha256sum.ps1" { $algo = "SHA256"; Break }
        "sha384sum.ps1" { $algo = "SHA384"; Break }
        "sha512sum.ps1" { $algo = "SHA512"; Break }
    }
    (Get-FileHash -algo $algo $filename).Hash + "  " + $filename
}

calcSignature( $firstArg )

Now I only have one script and the others are links pointing to sha256sum.ps1.

I'm guessing you're looking for "How to pass an argument to your .ps1 script".

This is an example of how the script sha256sum.ps1 would look:

[CmdletBinding(DefaultParameterSetName = 'Path')]
param(
    [Parameter(ParameterSetName = 'LiteralPath', Mandatory)]
    [string[]] $LiteralPath,

    [Parameter(ParameterSetName = 'Path', Mandatory, Position = 0)]
    [SupportsWildcards()]
    [string[]] $Path
)

(Get-FileHash @PSBoundParameters -Algorithm SHA256).Hash

Now, if we were to call this script, as an example:

PS \> .\sha256sum.ps1 .\test.html
1B24ED8C7929739D296DE3C5D6695CA40D8324FBF2F0E981CF03A8A6ED778C9C

Note: the current directory is where the script and the html file are located, if that was not the case, you should use the absolute path.

I would recommend you to the official docs to get a concept on functions and the param(...) block.