Add Get-StringHash - #63

Hi Ilya (@iSazonov), I'm your friendly neighborhood Microsoft Pull Request Bot (You can call me MSBOT). Thanks for your contribution!
You've already signed the contribution license agreement. Thanks!

The agreement was validated by Microsoft and real humans are currently evaluating your PR.

TTYL, MSBOT;

I love this idea.

Is Get the right verb? I usually only use the Get verb if there is an identical command I can pair with it that uses the Set verb, e.g. Get-Service, Set-Service. Since you don't set hashes, I think one of the following command names might be better:

• ConvertTo-Hash
• New-Hash
• Convert-StringToHash
• Measure-Hash

According to the Approved Verbs page, New should be used instead of "Create, Generate, Build, Make, or Allocate." Measure maps to "Calculate". I looked for a verb that was synonymous with "Compute", but didn't find one.

Get is because we already have Get-FileHash.

Steve Lee (@SteveL-MSFT) Fixed!

Ilya (@iSazonov) please open an issue for feedback on this RFC (look at the previous ones as an example) that way you get notified if someone comments. thanks!