The module oh-my-posh is the Windows equivalent of oh-my-zsh for Linux. It can help create pretty prompts which may provide visual aids with git (among other things?1). I stumbled upon this idea on this blog, but really, it’s a very commonly used module. I’m going to use the Windows Terminal.

Installing a NerdFont

oh-my-posh uses glyphs that are not present in standard fonts. To get them, we need to install one of many NerdFonts from the website. Windows Terminal by default uses Cascadia fonts. I prefer to use Fira Code instead. So we can just search for Fira Code in the website (or download any font - doesn’t really matter). The fonts will be downloaded in a zip format.

Install and check the name of the font in the font file. In my case, it is “FiraCode Nerd Font”. Now we can go to Terminal settings by pressing Ctrl+Shift+, which will open the settings in JSON format, and add this to the "profiles": "defaults": key:

"font": 
            {
                "face": "FiraCode Nerd Font"
            }

This is the place where we can adjust the size and style of the font if desired, e.g "size": 10. Save and Terminal refreshes, now using the installed NerdFont.

Shell-independent installation in Windows

From this guide. First, we need to install oh-my-posh. We can do this using winget, the package manager CLI in Windows:

winget install JanDeDobbeleer.OhMyPosh

Now we will have the oh-my-posh.exe application which we can use to customize our prompt. For WSL, this will be oh-my-posh-wsl instead. Themes are present at the location ~\AppData\Local\Programs\oh-my-posh\themes. We can list all the theme names:

ls ~\AppData\Local\Programs\oh-my-posh\themes\

which are just JSON files with the name format *.omp.json. To actually view the themes in action, however, we can run the following command:

Get-ChildItem -Path "~\AppData\Local\Programs\oh-my-posh\themes\*" -Include '*.omp.json' | Sort-Object Name | ForEach-Object -Process {
    $esc = [char]27
    Write-Host ""
    Write-Host "$esc[1m$($_.BaseName)$esc[0m"
    Write-Host ""
    oh-my-posh --config $($_.FullName) --pwd $PWD
    Write-Host ""
}

which basically loops through all the JSON files in the folder and prints a custom prompt for each. To actually change the prompt, we can run

oh-my-posh --init --shell pwsh --config ~/AppData/Local/Programs/oh-my-posh/themes/jandedobbeleer.omp.json | Invoke-Expression

in Powershell, or

eval "$(oh-my-posh-wsl --init --shell bash --config $USERPROFILE/AppData/Local/Programs/oh-my-posh/themes/jandedobbeleer.omp.json)"

on bash in WSL.2

To make changes permanent, we need to add this command to the profile of the respective shells ($profile for Powershell and .bashrc for bash).

Remarks

Even though it seems like a PITA3 to write such a complicated path again and again (especially in WSL), once we’ve written it, all we have to do is modify the name of the theme (here jandedobbeleer) and not touch the path at all. However, if we are to modify these themes to our liking, it is wise to copy the JSON files to another location and make necessary changes, and then make the shell profile point to that location.

Only for Powershell

To start with, we run:

Install-Module oh-my-posh -Scope CurrentUser

in Powershell. This installs the oh-my-posh module for the current user (admin privileges not required?).

  1. For instance, it marks the root folder of this Jekyll website with a little ruby icon (Jekyll uses Ruby and the root folder has a Gemfile) or a Python symbol when python files are present. ↩

  2. The environment variable $USERPROFILE does not exist by default. It has to be forwarded from Windows to WSL via the WSLENV variable:

    setx WSLENV USERPROFILE/up

    and after a session restart, the Windows environment variable %USERPROFILE% containing the path to the user profile is available at $USERPROFILE in WSL (translated to a Linux-style path, the /p switch does this). (Source) ↩

  3. Pain-In-The-Ass. ↩