Batch files - number of command line arguments

Question

Just converting some shell scripts into batch files and there is one thing I can\'t seem to find...and that is a simple count of the number of command line arguments.

<

Answer 1

If the number of arguments should be an exact number (less or equal to 9), then this is a simple way to check it:

if "%2" == "" goto args_count_wrong
if "%3" == "" goto args_count_ok

:args_count_wrong
echo I need exactly two command line arguments
exit /b 1

:args_count_ok

Answer 2

Avoids using either shift or a for cycle at the cost of size and readability.

@echo off
setlocal EnableExtensions EnableDelayedExpansion
set /a arg_idx=1
set "curr_arg_value="
:loop1
if !arg_idx! GTR 9 goto :done
set curr_arg_label=%%!arg_idx!
call :get_value curr_arg_value !curr_arg_label!
if defined curr_arg_value (
  echo/!curr_arg_label!: !curr_arg_value!
  set /a arg_idx+=1
  goto :loop1
)
:done
set /a cnt=!arg_idx!-1
echo/argument count: !cnt!
endlocal
goto :eof

:get_value
(
  set %1=%2
)

Output:

count_cmdline_args.bat testing more_testing arg3 another_arg

%1: testing
%2: more_testing
%3: arg3
%4: another_arg
argument count: 4

EDIT: The "trick" used here involves:

1. Constructing a string that represents a currently evaluated command-line argument variable (i.e. "%1", "%2" etc.) using a string that contains a percent character (%%) and a counter variable arg_idx on each loop iteration.

2. Storing that string into a variable curr_arg_label.

3. Passing both that string (!curr_arg_label!) and a return variable's name (curr_arg_value) to a primitive subprogram get_value.

4. In the subprogram its first argument's (%1) value is used on the left side of assignment (set) and its second argument's (%2) value on the right. However, when the second subprogram's argument is passed it is resolved into value of the main program's command-line argument by the command interpreter. That is, what is passed is not, for example, "%4" but whatever value the fourth command-line argument variable holds ("another_arg" in the sample usage).

5. Then the variable given to the subprogram as return variable (curr_arg_value) is tested for being undefined, which would happen if currently evaluated command-line argument is absent. Initially this was a comparison of the return variable's value wrapped in square brackets to empty square brackets (which is the only way I know of testing program or subprogram arguments which may contain quotes and was an overlooked leftover from trial-and-error phase) but was since fixed to how it is now.