CODEWITHSUNDEEP
windowsbatch-filecmdfindstr
Andy Moss
Andy Moss

Reputation: 33

Why do I have to escape my already escaped search string in a for loop in a batch file?

After trawling through S.O. I've managed to piece together my function so it works, but I don't understand something about it. I'm basically trying to ensure that a file I want to use doesn't have double quotes in it. I've used findstr with the /m option which is returning the filename.

When I run the command from the cmd line it works with this:

findstr /V /L /m "\"" filename.txt

When filename has no double quotes it returns the filename, if it does have double quote it returns blank / null /whatever. Exactly what I want.

So I wanted to capture this result in a variable, using a solution on this website. I've discovered this works:

setlocal enabledelayedexpansion
set test=
for /F %%a in ('findstr /V /L /m ^"^\^"^" filename.txt') do (@set test=!test! %%a)

echo %test%

So my question: My search string needs to be escaped so goes from:

"\""

and becomes:

^"^\^"^"

but I don't understand why I have to do that. Can anybody explain?

Upvotes: 2

Views: 111

Answers (1)

MC ND
MC ND

Reputation: 70943

To answer your question, the reason why your search string needs to be escaped (^ escaped) is ... none. In your case you search string does not need to be escaped. 

@echo off
    setlocal enableextensions disabledelayedexpansion

    for /f "delims=" %%a in ('
        findstr /l /m /v  "\"" *.txt
    ') do echo %%a

You need the \" escape because the findstr argument handling (more here) but the ^" scaping is not required.

But there are some cases where the ^ quote scaping is needed. The reason for the escaping in those cases is that the command inside the for /f is executed in a separate cmd instance. This started instance could (or not) include its own set of quotes

cmd /c " ...... "

and the quotes in your command could interfere in the cmd parsing of the command to execute.

But if you escape the quotes (cmd escaping, that is ^"), they will not be parsed as closing/opening quotes, but as a literal without a special meaning for the cmd parser, so they could be hadled later.

Upvotes: 1

Related Questions