Add --os option to dotnet restore command

Co-authored-by: marcpopMSFT <[email protected]>

Author: Copilot

documentation/manpages/sdk/dotnet-restore.1

@@ -26,11 +26,11 @@ dotnet-restore - Restores the dependencies and tools of a project.
 .IP
 .nf
 \f[C]
-dotnet restore [<ROOT>] [--configfile <FILE>] [--disable-build-servers]
+dotnet restore [<ROOT>] [-a|--arch <ARCHITECTURE>] [--configfile <FILE>] [--disable-build-servers]
     [--disable-parallel]
     [-f|--force] [--force-evaluate] [--ignore-failed-sources]
     [--interactive] [--lock-file-path <LOCK_FILE_PATH>] [--locked-mode]
-    [--no-cache] [--no-dependencies] [--packages <PACKAGES_DIRECTORY>]
+    [--no-cache] [--no-dependencies] [--os <OS>] [--packages <PACKAGES_DIRECTORY>]
     [-r|--runtime <RUNTIME_IDENTIFIER>] [-s|--source <SOURCE>]
     [--tl:[auto|on|off]] [--use-current-runtime, --ucr [true|false]]
     [--use-lock-file] [-v|--verbosity <LEVEL>]
@@ -144,6 +144,15 @@ If you use this option, don\[cq]t use the \f[V]-r|--runtime\f[R] option.
 Available since .NET 6 Preview 7.
 .RE
 .IP \[bu] 2
+\f[B]\f[VB]--os <OS>\f[B]\f[R]
+.RS 2
+.PP
+Specifies the target operating system (OS).
+This is a shorthand syntax for setting the Runtime Identifier (RID), where the provided value is combined with the default RID.
+For example, on a \f[V]win-x64\f[R] machine, specifying \f[V]--os linux\f[R] sets the RID to \f[V]linux-x64\f[R].
+If you use this option, don\[cq]t use the \f[V]-r|--runtime\f[R] option.
+.RE
+.IP \[bu] 2
 \f[B]\f[VB]--configfile <FILE>\f[B]\f[R]
 .RS 2
 .PP

src/Cli/dotnet/Commands/Restore/RestoreCommandParser.cs

@@ -73,6 +73,7 @@ private static Command ConstructCommand()
         }
 
         command.Options.Add(CommonOptions.ArchitectureOption);
+        command.Options.Add(CommonOptions.OperatingSystemOption);
         command.SetAction(RestoreCommand.Run);
 
         return command;