I can manually open up PowerShell and run

wsl
ip addr show eth0 | grep 'inet\b' | awk '{print $2}' | cut -d/ -f1

To get the IP address of the Ubuntu instance. But when I try to write a script for this (100 different ways) I always get some kind of error. This is an example

$command = "ip addr show eth0 | grep 'inet\b' | awk '{print $2}' | cut -d/ -f1"
$ip = Invoke-Expression "wsl $command"

Which gives an error about grep.

CodePudding user response：

Call wsl.exe via the -e option and specify bash as the executable, which allows you to use the latter's -c option with a command line specified as a single string:

# Note the need to escape $ as `$ 
# to prevent PowerShell from interpolating it up front inside "..."
$command = "ip addr show eth0 | grep 'inet\b' | awk '{print `$2}' | cut -d/ -f1"

wsl -e bash -c $command

A note re the choice of string literals on the PowerShell side:

• Using "..." quoting rather than '...' quoting is convenient if the text contains ' characters, because it obviates the need for escaping - ditto for the inverse scenario: using '...' quoting for text that contains " chars.

• However, as in POSIX-compatible shells such as Bash, the choice of quoting character matters:

  • '...' is a verbatim (single-quoted) string.

    • Unlike in POSIX-compatible shells, where escaping embedded ' chars. must be emulated with '\'', PowerShell does support direct escaping, namely with ''

  • "..." is an expandable (double-quoted) string, i.e. subject to string interpolation for substrings that start with $

    • Unlike in POSIX-compatible shells, where embedded $ chars. to be used verbatim (literally) require escaping as \$, in PowerShell you must use `$, using `, the so-called backtick, PowerShell's escape character.

CodePudding user response：

Or let's assume you have powershell installed in linux (there's no Get-NetIPConfiguration?).

$command = "ip addr show eth0 | select-string inet\b | % { (-split `$_)[1] } |
   % { (`$_ -split '/')[0] }"
wsl -e pwsh -c $command

10.0.0.107

Or even without it.

wsl -e ip addr show eth0 | select-string inet\b | % { (-split $_)[1] } |
  % { ($_ -split '/')[0] }

10.0.0.107