Remove quotes from named environement variables in Windows scripts

Question

I want to store a URL prefix in an Windows environment variable. The ampersands in the query string makes this troublesome though.

For example: I have a URL prefix of "http://example.com?foo=1&bar=", and want to create a full URL by providing a value for the bar param. I then want to launch that url using the "start" command.

Adding quotes around the value for the SET operation is easy enough:

set myvar="http://example.com?foo=1&bar="

Windows includes the quotes in the actual value though (thanks Windows!):

echo %myvar%
"http://example.com?foo=1&bar=true"

I know that I can strip quotes away from batch file arguments by using tilde:

echo %~1

However, I can't seem to do it to named variables:

echo %~myvar%
%~myvar%

What's the syntax for accomplishing this?

Answer 1

I think this should do it:

for /f "tokens=*" %i in (%myvar%) do set %myvar%=%~i

But you do not need this,

set myvar="http://example.com?foo=1&bar="
start "" %myvar%

Will work too, you just need to supply a title to the start command.

Answer 2

This is not a limitation of the environment variable, but rather the command shell.

Enclose the entire assignment in quotes:

set "myvar=http://example.com?foo=1&bar="

Though if you try to echo this, it will complain as the shell will see a break in there.

You can echo it by enclosing the var name in quotes:

echo "%myvar%"

Or better, just use the set command to view the contents:

set myvar

Answer 3

echo %myvar:"=%

Answer 4

Use delayed environment variable expansion and use !var:~1,-1! to remove the quotes:

@echo off
setlocal enabledelayedexpansion
set myvar="http://example.com?foo=1&bar="
set myvarWithoutQuotes=!myvar:~1,-1!
echo !myvarWithoutQuotes!