How to parse strings in a text file containing local variables using a Windows batch file?

Question

Suppose there's a text file:

abc %x%
def %y%

and a batch file:

setlocal
set x=123
set y=456
for /f %%i in (textfile.txt) do echo %%i

The output will be

abc %x%
def %y%

Is there any (simple) way to get this (without powershell or special executables)?

abc 123
def 456

for /f "delims=" %%i in (textfile.txt) do call echo %%i

Aacini
– Aacini

2016-12-10 02:38:50 +00:00
Commented Dec 10, 2016 at 2:38 — Aacini
– Aacini, Commented Dec 10, 2016 at 2:38

score 2 · Accepted Answer · 2016-12-11 20:29:43Z

2

There is a simpler way with the call

@Echo off
set x=123
set y=456
for /f "delims=" %%i in (textfile.txt) do call call echo %%i

A double call is only necessray if there are double percent signs surrounding the var. But they do harm only if you use double percent signs to halt expansion one level.

edited Dec 11, 2016 at 20:29

answered Dec 10, 2016 at 3:02

user6811411

Sign up to request clarification or add additional context in comments.

7 Comments

jmucchiello Over a year ago

my actual solution used "call set" as my actual goal was never to echo the data. I never did try "for...do call call".

dbenham Over a year ago

Why two CALLs? A single CALL will do

user6811411 Over a year ago

@dbenham no, did you test it? I did.

dbenham Over a year ago

Yes, I have confirmed that it works as I expected. I took your exact code, removed one CALL, and it continued to work.

jeb Over a year ago

@LotPings Even for Win10 your described behaviour would be very unexpected, as a CALL restarts the parser at the perecent expansion phase.

|

paxdiablo · Accepted Answer · 2016-12-10 02:16:07Z

1

You can use an extra level of calling to evaluate the text string as follows:

@echo off
setlocal
set x=123
set y=456
for /f "delims=" %%i in (textfile.txt) do call :evalecho %%i
endlocal
goto :eof

:evalecho
    echo %*
    goto :eof

The output of that for you input file is, as requested:

abc 123
def 456

answered Dec 10, 2016 at 2:16

paxdiablo

888k243 gold badges1.6k silver badges2k bronze badges

2 Comments

user6811411 Over a year ago

Took me some time to remember that you can force a second evaluation with stacked pseudo calls.

jmucchiello Over a year ago

I picked this answer because it was first and I never knew about the "call :label" syntax so it was also additionally educational.

Collectives™ on Stack Overflow

How to parse strings in a text file containing local variables using a Windows batch file?

2 Answers 2

7 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

7 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related