Sometime after 7.0, a new ETS script property named CommandLine was introduced for System.Diagnostics.Process instances, so that you could query a given process' command line.; e.g.:

# Currently Windows and Linux only: get the PowerShell session's own command line.
(Get-Process -Id $PID).CommandLine

As an aside: The property doesn't yet support macOS - see #13943.

On Linux, this is in effect implemented via the following command, using Linux' special files:

Get-Content /proc/$PID/cmdline 

The problem is that the content of these files contains the verbatim arguments as originally used during process creation separated with NUL characters, which in the terminal - due to NUL getting ignored - presents like directly joined arguments, which is unhelpful to the human observer.

The question is how much effort we want to expend to present a functional command line that is the equivalent of the original:

• A simple solution would be to simply space-concatenate the verbatim arguments -
  (Get-Content /proc/$PID/cmdline) -replace "`0", ' ' - for a friendlier presentation:

  • This results in loss of information: the original argument boundaries aren't preserved.
  • However, it may be good enough for the human observer, and it is what the standard ps utility does with -o command=, which is the only similarly simple solution for macOS - see Make the .CommandLine ETS script property on Process objects work on macOS too #13943.

• Trying to recreate a functional command line would require substantially more effort - namely for recreating required quoting and escaping - and has an inherent conceptual problem:

  • Given that PowerShell syntax differs from that of POSIX-compatible shells: which shell's syntax do you use for the reconstruction? Arguably, it should be PowerShell's (which, of course, is still fundamentally hampered by Arguments for external executables aren't correctly escaped #1995).

Steps to reproduce

On Linux, from PowerShell"

pwsh -noprofile -command 'Get-Content /proc/$PID/cmdline'

Expected behavior

A string with the following verbatim content:

/usr/bin/pwsh -noprofile -command Get-Content /proc/$PID/cmdline

This assumes simple space concatenation without any attempt to recreated required quoting and escaping; see discussion above.

Actual behavior

Since the verbatim arguments are NUL-concatenated, they appear as directly concatenated; note the lack of spaces between pwsh, -noprofile, -command, and the latter's argument:

/usr/bin/pwsh-noprofile-commandGet-Content /proc/$PID/cmdline

Environment data

PowerShell Core 7.1.0-rc.2