"Eval" in MS-DOS batch file?

[kevinpauli]

Sorry if this is a very basic question, but surprisingly, extensive googling on the topic has yielded nothing of value.

How do I do an "eval" in MS-DOS?

The task at hand is to capture the current hostname in a variable so I can use it elsewhere in the script.  I found the "hostname" command, which when executed spits out the hostname.  What I want to do is grab the output of the hostname command and store in in a variable.

I am thinking there must be some kind of directive in the batch file, either special characters surrounding the expression, or some kind of a switch, to say "don't treat this string as a LITERAL, instead EVALUATE it and return me the result". 

Help?

[BC_Programmer]

set /a can be used for doing arithmetic, I think it works for strings to.

[kevinpauli]

C:/>set /a hname = hostname
0
C:/>echo %hname%
0

[kevinpauli]

I found something that works.  Ugly, but it works.

@echo off
for /f "tokens=* delims= " %%a in ('hostname') do (
set HOST=%%a
)
echo %HOST%

[BC_Programmer]

I thought you wanted to evaluate an expression- not redirect the output of a command into a variable. Although rereading your original post makes it quite clear this was your intention. Sorry if I misled you.

[Dias de verano]

1. You can get it all on one line.

Code: [Select]

for /f "tokens=* delims= " %%a in ('hostname') do set HOST=%%a
2. The tokens/delims block looks a little odd. As in redundant. Spaces as delims, when they are the default, and I think host names don't have any spaces anyway, so the tokens bit is redundant too, but I am ready to be corrected.

3. On my XP system, you can get the same result, but with alpha chars in upper case, by merely expanding the system variable %userdomain% but maybe that won't be true for all systems?

Code: [Select]

C:\>for /f %a in ('hostname') do @echo %a
pupp-c92f25ed23

C:\>echo %userdomain%
PUPP-C92F25ED23


[rets0815]

Code: [Select]

C:\>echo %userdomain%
PUPP-C92F25ED23

the above command will not give you the hostname, instead it will print the domain. So I guess you use a local account for logging into your computer.