SET Command Doesn't Echo FOR /F Loop Parameter Values [duplicate] - windows

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How does the Windows Command Interpreter (CMD.EXE) parse scripts?
(8 answers)
Closed 3 years ago.
I ran across an issue using the SET command inside a FOR /F loop to echo the values of the loop parameters (e.g., %%g, %%h, etc.). I used the SET command because I wanted to see what values get assigned to each FOR /F loop parameter when the FOR /F loop iterates. I am specifically looking to see how many caret escape characters (^) are stripped by the CMD parser as it processes the line of test code that is the last element in the $code_test[00] array record:
#echo off
setlocal disabledelayedexpansion
set $code_test[00]=Record [00],2,green,blue,if not exist ^^!$m^^!^^!$n^^! (set /a $result+=3)
echo Value using ECHO command:
echo $code_test[00] = %$code_test[00]%
echo.
echo Value using SET command with Delayed Expansion DISABLED:
set $code_test[
echo.
setlocal enabledelayedexpansion
echo Value using SET command with Delayed Expansion ENABLED:
set $code_test[
echo.
for /f "tokens=1-10 delims=," %%g in ('set $code_test[') do (
echo For /f loop values using ECHO command ...
echo g = %%g
echo h = %%h
echo i = %%i
echo j = %%j
echo k = %%k
echo.
echo For /f loop values using SET command ...
set %%g
set %%h
set %%i
set %%j
set %%k
)
The code populates one record for the $code_test[xx] array with various elements, the last of which is a Windows CMD test code statement. I want to see the value of the FOR /F loop parameter that corresponds to this test code statement, which is %%k. So, I used both the echo and set commands to echo the value of %%k to see if %%k retained the caret (^) escape characters that were present in the original test code definition for $code_test[00]. The echo command worked as expected and stripped the caret escape characters (^) from the code. But the set command completely failed. I've read the post about how the CMD interpreter parses code here and I didn't see an answer to my question.
I realize that dealing with FOR /F loop parameters can be tricky. Should I just assume that I can't deal with FOR /F loop parameters directly (e.g., set %%k) and make it a policy to always assign the value of a FOR /F parameter to an environment variable then deal with the environment variable instead of the FOR /F parameter?

Answer 1

SET "blue62=108"
SET "%%%%k=hello"
ECHO after SET %%%%%%%% k errorlevel=!errorlevel!
set|FIND "k="
echo For /f loop values using SET command ...
ECHO ++++++++++++++++!errorlevel!
set %%g
set %%h
set %%i
set %%j
ECHO :::::::::::::::::::::!errorlevel!
SET if not exist !$m!!$n! (set /a $result+=3)
ECHO -----------!errorlevel!-------------------
ECHO :::::::::::::::::::::!errorlevel!
SET "if not exist !$m!!$n! (set /a $result+=3)"
ECHO -----------!errorlevel!-------------------
set %%k
)
I expanded your reporting to include the above code with these results:
For /f loop values using ECHO command ...
g = $code_test[00]=Record [00]
h = 2
i = green
j = blue
k = if not exist !$m!!$n! (set /a $result+=3)
after SET %%%% k errorlevel=0
For /f loop values using SET command ...
++++++++++++++++1
Environment variable 2 not defined
Environment variable green not defined
blue62=108
:::::::::::::::::::::1
-----------1-------------------
:::::::::::::::::::::1
-----------1-------------------
Environment variable %k not defined
I believe this demonstrates that set simply acts strangely if confronted with an argument that is not a simple space-absent string with optional = for assignment.
What was really curious was that the Environment variable %k not defined did not appear with the original code.
I believe you're really expecting a 1970's vintage design to not only be bullet-proof but act in a consistent manner when supplied with unanticipated data. Just treat it like your grandma. Very capable, but easily confused.