How to run bash commands from pwsh? - bash

Question

We have a powershell script which is 99% cross-platform but occasionally we need an IF LINUX THEN branch because of how different windows and linux service management is.
We would like to run the kill command from bash but this is an alias of the powershell Stop-Process.
How do we run native bash commands like ps, kill and ls from Powershell.
Note sh ps or bash ps do not work.
PS > bash ps
/usr/bin/ps: /usr/bin/ps: cannot execute binary file

Answer 1

Assuming that running bash runs bash from pwsh, you would want bash -c "ps". Normally the argument to bash would be a script that it tries to execute, hence the error "cannot exxecute binary file". ps is not a bash script, but an executable binary. The -c on the other hand runs arbitrary bash code provided as a command line argument, which can obviously run programs like ps.

Answer 2

If you know the location of the command you can just run it:
/usr/bin/kill
Usage:
kill [options] <pid|name]...
...
Otherwise which can find it and run it with Invoke-Expression or iex:
which kill | iex
This can get tricky since which could return multiple lines which you then would have to guess and just take the first one. You also need to somehow add parameters (e.g. 123) to your command:
which kill | select -first 1 | % {iex "$_ 123"}
kill: sending signal to 123 failed: No such process

Answer 3

Had lots of trouble running ant -version from pwsh but this works:
Invoke-Expression "/bin/bash ant -version"
Cross-Platform Function
function RunCommand($Command) {
if($env:OS -eq 'Windows_NT') {
CMD /c $Command
} else {
Invoke-Expression "/bin/bash $Command"
}
}