Commenting multiple lines in DOS batch file - batch-file

Question

I have written huge MS DOS Batch file. To test this batch file I need to execute some lines only and want to hide/comment out remaining.
I have some existing comment lines starting with :: hence I cannot use :: anymore as it will scramble all comments.
How can I solve this problem?

Answer 1

You can use a goto to skip over code.
goto comment
...skip this...
:comment

Answer 2

If you want to add REM at the beginning of each line instead of using GOTO, you can use Notepad++ to do this easily following these steps:
Select the block of lines
hit Ctrl-Q
Repeat steps to uncomment

Answer 3

break||(
code that cannot contain non paired closing bracket
)
While the goto solution is a good option it will not work within brackets (including FOR and IF commands).But this will. Though you should be careful about closing brackets and invalid syntax for FOR and IF commands because they will be parsed.
Update
The update in the dbenham's answer gave me some ideas.
First - there are two different cases where we can need multi line comments - in a bracket's context where GOTO cannot be used and outside it.
Inside brackets context we can use another brackets if there's a condition which prevents the code to be executed.Though the code thede will still be parsed
and some syntax errors will be detected (FOR,IF ,improperly closed brackets, wrong parameter expansion ..).So if it is possible it's better to use GOTO.
Though it is not possible to create a macro/variable used as a label - but is possible to use macros for bracket's comments.Still two tricks can be used make the GOTO
comments more symetrical and more pleasing (at least for me). For this I'll use two tricks - 1) you can put a single symbol in front of a label and goto will still able
to find it (I have no idea why is this.My guues it is searching for a drive). 2) you can put a single :
at the end of a variable name and a replacement/subtring feature will be not triggered (even under enabled extensions). Wich combined with the macros for brackets comments can
make the both cases to look almost the same.
So here are the examples (in the order I like them most):
With rectangular brackets:
#echo off
::GOTO comment macro
set "[:=goto :]%%"
::brackets comment macros
set "[=rem/||(" & set "]=)"
::testing
echo not commented 1
%[:%
multi
line
comment outside of brackets
%:]%
echo not commented 2
%[:%
second multi
line
comment outside of brackets
%:]%
::GOTO macro cannot be used inside for
for %%a in (first second) do (
echo first not commented line of the %%a execution
%[%
multi line
comment
%]%
echo second not commented line of the %%a execution
)
With curly brackets:
#echo off
::GOTO comment macro
set "{:=goto :}%%"
::brackets comment macros
set "{=rem/||(" & set "}=)"
::testing
echo not commented 1
%{:%
multi
line
comment outside of brackets
%:}%
echo not commented 2
%{:%
second multi
line
comment outside of brackets
%:}%
::GOTO macro cannot be used inside for loop
for %%a in (first second) do (
echo first not commented line of the %%a execution
%{%
multi line
comment
%}%
echo second not commented line of the %%a execution
)
With parentheses:
#echo off
::GOTO comment macro
set "(:=goto :)%%"
::brackets comment macros
set "(=rem/||(" & set ")=)"
::testing
echo not commented 1
%(:%
multi
line
comment outside of brackets
%:)%
echo not commented 2
%(:%
second multi
line
comment outside of brackets
%:)%
::GOTO macro cannot be used inside for loop
for %%a in (first second) do (
echo first not commented line of the %%a execution
%(%
multi line
comment
%)%
echo second not commented line of the %%a execution
)
Mixture between powershell and C styles (< cannot be used because the redirection is with higher prio.* cannot be used because of the %*) :
#echo off
::GOTO comment macro
set "/#:=goto :#/%%"
::brackets comment macros
set "/#=rem/||(" & set "#/=)"
::testing
echo not commented 1
%/#:%
multi
line
comment outside of brackets
%:#/%
echo not commented 2
%/#:%
second multi
line
comment outside of brackets
%:#/%
::GOTO macro cannot be used inside for loop
for %%a in (first second) do (
echo first not commented line of the %%a execution
%/#%
multi line
comment
%#/%
echo second not commented line of the %%a execution
)
To emphase that's a comment (thought it is not so short):
#echo off
::GOTO comment macro
set "REM{:=goto :}REM%%"
::brackets comment macros
set "REM{=rem/||(" & set "}REM=)"
::testing
echo not commented 1
%REM{:%
multi
line
comment outside of brackets
%:}REM%
echo not commented 2
%REM{:%
second multi
line
comment outside of brackets
%:}REM%
::GOTO macro cannot be used inside for
for %%a in (first second) do (
echo first not commented line of the %%a execution
%REM{%
multi line
comment
%}REM%
echo second not commented line of the %%a execution
)

Answer 4

Another option is to enclose the unwanted lines in an IF block that can never be true
if 1==0 (
...
)
Of course nothing within the if block will be executed, but it will be parsed. So you can't have any invalid syntax within. Also, the comment cannot contain ) unless it is escaped or quoted. For those reasons the accepted GOTO solution is more reliable. (The GOTO solution may also be faster)
Update 2017-09-19
Here is a cosmetic enhancement to pdub's GOTO solution. I define a simple environment variable "macro" that makes the GOTO comment syntax a bit better self documenting. Although it is generally recommended that :labels are unique within a batch script, it really is OK to embed multiple comments like this within the same batch script.
#echo off
setlocal
set "beginComment=goto :endComment"
%beginComment%
Multi-line comment 1
goes here
:endComment
echo This code executes
%beginComment%
Multi-line comment 2
goes here
:endComment
echo Done
Or you could use one of these variants of npocmaka's solution. The use of REM instead of BREAK makes the intent a bit clearer.
rem.||(
remarks
go here
)
rem^ ||(
The space after the caret
is critical
)

Answer 5

Just want to mention that pdub's GOTO solution is not fully correct in case :comment label appear in multiple times. I modify the code from this question as the example.
#ECHO OFF
SET FLAG=1
IF [%FLAG%]==[1] (
ECHO IN THE FIRST IF...
GOTO comment
ECHO "COMMENT PART 1"
:comment
ECHO HERE AT TD_NEXT IN THE FIRST BLOCK
)
IF [%FLAG%]==[1] (
ECHO IN THE SECOND IF...
GOTO comment
ECHO "COMMENT PART"
:comment
ECHO HERE AT TD_NEXT IN THE SECOND BLOCK
)
The output will be
IN THE FIRST IF...
HERE AT TD_NEXT IN THE SECOND BLOCK
The command ECHO HERE AT TD_NEXT IN THE FIRST BLOCK is skipped.

Answer 6

#jeb
And after using this, the stderr seems to be inaccessible
No, try this:
#echo off 2>Nul 3>Nul 4>Nul
ben ali
mubarak 2>&1
gadeffi
..next ?
echo hello Tunisia
pause
But why it works?
sorry, i answer the question in frensh:
( la redirection par 3> est spécial car elle persiste, on va l'utiliser pour capturer le flux des erreurs 2> est on va le transformer en un flux persistant à l'ade de 3> ceci va
nous permettre d'avoir une gestion des erreur pour tout notre environement de script..par la suite si on veux recuperer le flux 'stderr' il faut faire une autre redirection du handle 2> au handle 1> qui n'est autre que la console.. )

Answer 7

try this:
#echo off 2>Nul 3>Nul 4>Nul
ben ali
mubarak
gadeffi
..next ?
echo hello Tunisia
pause