Running powershell script inside a bash script

Are you trying

.\scriptfile.ps1

? That should be

./scriptfile.ps1

But also, when invoking powershell from a bash script, you'll need to either run the pwsh command like

pwsh ./scriptfile.ps1

or the first line of your Powershell script file should be a shebang (interpreter directive) like:

#!/usr/bin/env pwsh

See How can I use a shebang in a PowerShell script?

I'm using git bash on Windows 10 Pro and there it's powershell. The executable is in /c/WINDOWS/System32/WindowsPowerShell/v1.0/powershell.exe and it's contained in my $PATH. So I can say

powershell ./scriptfile.ps1
# or inline:
powershell 'my script'

In the Ubuntu-on-Windows bash I have to say

powershell.exe ./scriptfile.ps1

try to change permission and make it excutable with chmod +x file.ps1

# Update the list of packages
sudo apt-get update
# Install pre-requisite packages.
sudo apt-get install -y wget apt-transport-https software-properties-common
# Download the Microsoft repository GPG keys
wget -q https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb
# Register the Microsoft repository GPG keys
sudo dpkg -i packages-microsoft-prod.deb
# Update the list of products
sudo apt-get update
# Enable the "universe" repositories
sudo add-apt-repository universe
# Install PowerShell
sudo apt-get install -y powershell
# Start PowerShell
pwsh