PowerShell 7 ships with fish-style autosuggestions

I was pair programming on the Windows box I have to use for work, and a script we needed to run died on the spot:

I read it twice and was none the wiser. I am still in my scared phase on Windows. Instead of taking a deep breath and reading what the error says, I panic and understand nothing. My shell was PowerShell. What more did it want?

Fernando, who I was pairing with, understood it right away: I was running a Windows NT shell, the ancient one Windows still ships as its default. PowerShell 7 is a separate program, installed next to the old one, not on top of it. The script had said so in its first line:

# deploy.ps1#Requires -Version 7

He told me to install the new shell:

winget install --id Microsoft.PowerShell

I will not claim I fully grasp the 5.1 story. The short version: Windows PowerShell 5.1 is frozen, PowerShell 7 is its cross-platform successor, and both live side by side on the same machine.

The script ran. That was supposed to be the whole story. Then I typed my first command into the new shell, and gray text appeared ahead of my cursor. The shell was finishing my sentence, fish-style, from history:

The feature is Predictive IntelliSense, part of PSReadLine, and it is on by default since PSReadLine 2.2.6, which shipped with PowerShell 7.3. The old shell never showed me this because it bundles a PSReadLine that predates the feature entirely:

Windows PowerShellCopyright (C) Microsoft Corporation. All rights reserved.Install the latest PowerShell for new features and improvements! https://aka.ms/PSWindows$ $PSVersionTable.PSVersionMajor  Minor  Build  Revision-----  -----  -----  --------5      1      26100  8655$ (Get-Module PSReadLine).VersionMajor  Minor  Build  Revision-----  -----  -----  --------2      0      0      -1

Predictions arrived in PSReadLine 2.1.0. The new shell is years past that:

PowerShell 7.6.3$ (Get-Module PSReadLine).VersionMajor  Minor  Build  Revision-----  -----  -----  --------2      4      5      -1

A newer PSReadLine could have been bolted onto 5.1, it turns out. And the old shell had been telling me the whole time, right there in its banner. I stopped reading that banner years ago.

The suggestions felt instantly familiar for a reason: both shells write to the same PSReadLine history file. The brand-new shell already knew every command I had ever typed into the old one. Its very first suggestion was the winget line that had installed it, minutes earlier, from the other side.

One gotcha: installing PowerShell 7 changes nothing visible. Windows Terminal kept opening the old shell in every new tab until I pointed Settings > Startup > Default profile at “PowerShell”. The one without “Windows” in front is the new one.

I still do not like Windows. But I am starting to feel at home in its terminal, and getting there was less work than my last zsh setup.

P.S. f2. yes, yes, and yes again

I only learned this while writing the post: pressing f2 flips the inline suggestion into a dropdown of matching commands from history, straight from the docs. A TIL inside the TIL.