Using "setlocal enabledelayedexpansion" in cmd prompt

Question

Does setlocal enabledelayedexpansion only work in a batch file? How can setlocal enabledelayedexpansion be used in a cmd prompt?

score 3 · Accepted Answer · answered May 15 '15 at 05:35

3

You can enable delayed expansion in a command prompt with the command cmd /V:ON

From cmd /?:

/V:ON   Enable delayed environment variable expansion using ! as the
        delimiter. For example, /V:ON would allow !var! to expand the
        variable var at execution time.  The var syntax expands variables
        at input time, which is quite a different thing when inside of a FOR
        loop.

answered May 15 '15 at 05:35

SomethingDark

13,229
5
50
55

@user15964 - When you combine commands like that, they are all interpreted within the context of the current environment, so `command` is treated like it is still in the `/V:OFF` cmd prompt. A one-liner like you want is not possible. – SomethingDark May 15 '15 at 05:42
I stand corrected. (To be fair, I can't imagine a single situation where I would ever be forced to use a one-liner.) The information about the environment not changing is still good, so I won't delete the comment. – SomethingDark May 15 '15 at 07:36
@PetSerAl Are you sure? `cmd /v:on /c command` didn't works for me – user15964 May 15 '15 at 07:56
@user15964 I type `set var=value&cmd /v:on /c echo !var!` in my `cmd` prompt, and I got `value` printed, as result. – user4003407 May 15 '15 at 11:15

score 1 · Answer 2 · answered May 15 '15 at 07:04

Learn by example: Copy&Paste from my CMD window:

==>echo !os! %pp%
!os! %pp%

==>cmd /E:ON /V:ON /K set "pp=yy" & set pp & echo !os! !pp!

==>echo !os! %pp%
Windows_NT yy

==>exit
Environment variable pp  not defined
!os! !pp!

==>cmd /E:ON /V:ON /K set "pp=yy" ^& set pp ^& echo !os! !pp!
pp=yy
Windows_NT yy

==>echo !os! %pp%
Windows_NT yy

==>exit

==>echo !os! %pp%
!os! %pp%

==>

Explanation:

echo !os! %pp% returns !os! %pp% showing delayed expansion disabled and pp variable not defined in current CLI;
cmd /E:ON /V:ON /K set "pp=yy" & set pp & echo !os! !pp! returns nothing, new instance of the Windows command interpreter has delayed expansion enabled (see echo !os! %pp% output);
exit returns result of set pp & echo !os! !pp! in a parent CLI instance: Environment variable pp not defined and !os! !pp!;
cmd /E:ON /V:ON /K set "pp=yy" ^& set pp ^& echo !os! !pp! returns pp=yy and Windows_NT yy in the new CLI instance (note all & escaped by ^);
echo !os! %pp% returns Windows_NT yy in the new CLI instance (it shows delayed expansion enabled and pp variable defined in the child CLI);
exit to a parent CLI instance;
echo !os! %pp% returns !os! %pp% again.

Using "setlocal enabledelayedexpansion" in cmd prompt

2 Answers2