Why variable doesn't work inside for /F command? - windows

If you have a variable inside this for /f command, it doesn't get printed out to file.
setlocal EnableDelayedExpansion
for /F %%i in ('dir /B') do (
set duration=asdf
echo %duration% > file.txt
)
Contents of file.txt: Echo is ON.
If you move set duration=asdf out of for /f wrap and put it below setlocal line it works correct and prints asdf into file.txt
Why? How do I do this with the set variable inside the for command?

This is due to delayed expansion, which stops variables from being set and used, in the same command.
You are getting Echo is ON. in file.txt, because to the command interpreter it's reading the echo command as:
echo > file.txt
Which as documented by echo /?
Type ECHO without parameters to display the current echo setting.
The simplest fix is to replace the % with !
Updated script:
setlocal EnableDelayedExpansion
for /F %%i in ('dir /B') do (
set duration=asdf
echo !duration! > file.txt
)

Related

Windows cmd batch file write multiple netstat outputs to text file [duplicate]

This question already has an answer here:
Variables are not behaving as expected
(1 answer)
Closed 3 years ago.
I have a list of host names separated by new lines in a text file. I want to run netstat on each of those lines and write the output of all these commands to a text file. I know the netstat command will work on each line so thats not an issue.
Here is what I have so far in my .bat:
FOR /F "tokens=*" %%A in (fqdn.txt) do (
FOR /F "tokens=* USEBACKQ" %%F IN (`netstat %%A`) DO (
SET var=%%F
)
echo %var% >> test.txt
echo delim >> test.txt
)
All that happens is the netstat help is posted to the command line over and over and the text file fills up with:
ECHO is on.
delim
ECHO is on.
delim
ECHO is on.
delim
Thanks in advance for the help :)
You need delayedexpansion because you are setting and using a variable inside of a code block:
#echo off
setlocal enabledelayedexpansion
for /f "tokens=*" %%A in (fqdn.txt) do (
for /f "tokens=* USEBACKQ" %%F IN (`netstat %%A`) DO (
SET var=%%F
)
echo !var! >> test.txt
echo delim >> test.txt
)
To get more detail on delayedexpansion run from cmd set /? and setlocal /?
That being said, you also do not need delayedexpansion:
#echo off
for /f "tokens=*" %%A in (fqdn.txt) do (
for /f "tokens=* USEBACKQ" %%F IN (`netstat %%A`) DO (
echo %%F >> test.txt
)
echo delim >> test.txt
)
As I did not see the actual input file, it is also possible to eliminate the second for loop should you want the entire output from the netstat command.
#echo off
(for /f "tokens=*" %%i in (fqdn.txt) do (
netstat %%i
echo delim
)
)>>test.txt

Why doesn't this batch script work? Reading lines from file

ok, I give up. Why doesn't this work?
setlocal ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
FOR /F %%I in (myfile.txt) do (
echo I: %%i
set LINE=%%i
echo LINE: %LINE%
)
"echo I:" displays the lines correctly, but "echo LINE:" is empty
I have tried different variations with the same results, such as
set LINE=%i
set LINE=%i%
set LINE=!i!
Obviously there is something simple I am not understanding.
you enabled delayed expansion, so the only thing you have to do is: use it.
replace echo LINE: %LINE% with echo LINE: !LINE!
EDIT: solution without delayed extension
FOR /F %%I in (myfile.txt) do ( call DoIt %%I )
exit /b
:DoIt
echo I: %1
set LINE=%1
echo LINE: %LINE%
goto :eof

Windows CMD FOR loop

I'm trying to make a code which will get first words from all lines of HELP's output to a variable and echo this variable. Here is my code:
#echo off
set a=
for /F "tokens=1,*" %%i in ('help') do (
set a=%a% %%i
)
echo %a%
But it returns first word from only last line. Why?
Bali C solved your problem as stated, but it looks to me like you are trying to get a list of commands found in HELP.
Some of the commands appear on multiple lines, so you get some extraneous words. Also there is a leading and trailing line beginning with "For" on an English machine that is not wanted.
Here is a short script for an English machine that will build a list of commands. The FINDSTR command will have to change for different languages.
#echo off
setlocal enableDelayedExpansion
set "cmds="
for /f "eol= delims=." %%A in ('help^|findstr /bv "For"') do (
for /f %%B in ("%%A") do set "cmds=!cmds! %%B"
)
set "cmds=%cmds:~1%"
echo %cmds%
EDIT
Ansgar Wiechers came up with a more efficient algorithm to extract just the command names at https://stackoverflow.com/a/12733642/1012053 that I believe should work with all languages. I've used his idea to simplify the code below.
#echo off
setlocal enableDelayedExpansion
set "cmds="
for /f %%A in ('help^|findstr /brc:"[A-Z][A-Z]* "') do set "cmds=!cmds! %%A"
set "cmds=%cmds:~1%"
echo %cmds%
You need to use delayed expansion in your for loop
#echo off
setlocal enabledelayedexpansion
set a=
for /F "tokens=1,*" %%i in ('help') do (
set a=!a! %%i
)
echo %a%
Instead of using %'s around the a variable, you use !'s to use delayed expansion.
Because the echo is outside the do ( ...... )
#echo off
for /F "tokens=1,*" %%i in ('help') do (
echo %%i
)
and no need to print a, you can use directly %%i.
Another very simple example could be a batch like this saved as help1.cmd
#echo off
for /F "tokens=1,*" %%i in ('help') do (
if /I "%%i" EQU "%1" echo %%j
)
and you call this batch like
help1 MKDIR
to get the short help text for the MKDIR command

Set ECHO / TYPE output as a Variable in Batch Files

Is it possible to set the output of TYPE or ECHO as a variable in a batch file?
Convoluted, and it only works for a single line, but general:
for /f "delims=" %%x in ('some command with output') do set "Var=%%x"
For echo you don't need to do anything special, just change
echo Foo
into
set Var=Foo
And for files there is also the option of either
set /p Var=<file.txt
or
for /f "delims=" %%x in (file.txt) do set "Var=%%x"

How do I get the result of a command in a variable in windows? [duplicate]

This question already has answers here:
Assign output of a program to a variable using a MS batch file
(12 answers)
How to set commands output as a variable in a batch file [duplicate]
(9 answers)
Closed 9 months ago.
I'm looking to get the result of a command as a variable in a Windows batch script (see how to get the result of a command in bash for the bash scripting equivalent). A solution that will work in a .bat file is preferred, but other common windows scripting solutions are also welcome.
The humble for command has accumulated some interesting capabilities over the years:
D:\> FOR /F "delims=" %i IN ('date /t') DO set today=%i
D:\> echo %today%
Sat 20/09/2008
Note that "delims=" overwrites the default space and tab delimiters so that the output of the date command gets gobbled all at once.
To capture multi-line output, it can still essentially be a one-liner (using the variable lf as the delimiter in the resulting variable):
REM NB:in a batch file, need to use %%i not %i
setlocal EnableDelayedExpansion
SET lf=-
FOR /F "delims=" %%i IN ('dir \ /b') DO if ("!out!"=="") (set out=%%i) else (set out=!out!%lf%%%i)
ECHO %out%
To capture a piped expression, use ^|:
FOR /F "delims=" %%i IN ('svn info . ^| findstr "Root:"') DO set "URL=%%i"
If you have to capture all the command output you can use a batch like this:
#ECHO OFF
IF NOT "%1"=="" GOTO ADDV
SET VAR=
FOR /F %%I IN ('DIR *.TXT /B /O:D') DO CALL %0 %%I
SET VAR
GOTO END
:ADDV
SET VAR=%VAR%!%1
:END
All output lines are stored in VAR separated with "!".
But if only a single-line console-output is expected, try:
#ECHO off
#SET MY_VAR=
FOR /F %%I IN ('npm prefix') DO #SET "MY_VAR=%%I"
#REM Do something with MY_VAR variable...
#John: is there any practical use for this? I think you should watch PowerShell or any other programming language capable to perform scripting tasks easily (Python, Perl, PHP, Ruby)
To get the current directory, you can use this:
CD > tmpFile
SET /p myvar= < tmpFile
DEL tmpFile
echo test: %myvar%
It's using a temp-file though, so it's not the most pretty, but it certainly works! 'CD' puts the current directory in 'tmpFile', 'SET' loads the content of tmpFile.
Here is a solution for multiple lines with "array's":
#echo off
rem ---------
rem Obtain line numbers from the file
rem ---------
rem This is the file that is being read: You can replace this with %1 for dynamic behaviour or replace it with some command like the first example i gave with the 'CD' command.
set _readfile=test.txt
for /f "usebackq tokens=2 delims=:" %%a in (`find /c /v "" %_readfile%`) do set _max=%%a
set /a _max+=1
set _i=0
set _filename=temp.dat
rem ---------
rem Make the list
rem ---------
:makeList
find /n /v "" %_readfile% >%_filename%
rem ---------
rem Read the list
rem ---------
:readList
if %_i%==%_max% goto printList
rem ---------
rem Read the lines into the array
rem ---------
for /f "usebackq delims=] tokens=2" %%a in (`findstr /r "\[%_i%]" %_filename%`) do set _data%_i%=%%a
set /a _i+=1
goto readList
:printList
del %_filename%
set _i=1
:printMore
if %_i%==%_max% goto finished
set _data%_i%
set /a _i+=1
goto printMore
:finished
But you might want to consider moving to another more powerful shell or create an application for this stuff. It's stretching the possibilities of the batch files quite a bit.
you need to use the SET command with parameter /P and direct your output to it.
For example see http://www.ss64.com/nt/set.html. Will work for CMD, not sure about .BAT files
From a comment to this post:
That link has the command "Set /P
_MyVar=<MyFilename.txt" which says it will set _MyVar to the first line
from MyFilename.txt. This could be
used as "myCmd > tmp.txt" with "set
/P myVar=<tmp.txt". But it will only
get the first line of the output, not
all the output
Example to set in the "V" environment variable the most recent file
FOR /F %I IN ('DIR *.* /O:D /B') DO SET V=%I
in a batch file you have to use double prefix in the loop variable:
FOR /F %%I IN ('DIR *.* /O:D /B') DO SET V=%%I
I would like to add a remark to the above solutions:
All these syntaxes work perfectly well IF YOUR COMMAND IS FOUND WITHIN THE PATH or IF THE COMMAND IS A cmdpath WITHOUT SPACES OR SPECIAL CHARACTERS.
But if you try to use an executable command located in a folder which path contains special characters then you would need to enclose your command path into double quotes (") and then the FOR /F syntax does not work.
Examples:
$ for /f "tokens=* USEBACKQ" %f in (
`""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" Hello '"F:\GLW7\Distrib\System\Shells and scripting"'`
) do echo %f
The filename, directory name, or volume label syntax is incorrect.
or
$ for /f "tokens=* USEBACKQ" %f in (
`"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'F:\GLW7\Distrib\System\Shells' is not recognized as an internal or external command, operable program or batch file.
or
`$ for /f "tokens=* USEBACKQ" %f in (
`""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello' is not recognized as an internal or external command, operable program or batch file.
In that case, the only solution I found to use a command and store its result in a variable is to set (temporarily) the default directory to the one of command itself :
pushd "%~d0%~p0"
FOR /F "tokens=* USEBACKQ" %%F IN (
`FOLDERBROWSE "Hello world!" "F:\GLW7\Distrib\System\Layouts (print,display...)"`
) DO (SET MyFolder=%%F)
popd
echo My selected folder: %MyFolder%
The result is then correct:
My selected folder: F:\GLW7\Distrib\System\OS install, recovery, VM\
Press any key to continue . . .
Of course in the above example, I assume that my batch script is located in the same folder as the one of my executable command so that I can use the "%~d0%~p0" syntax. If this is not your case, then you have to find a way to locate your command path and change the default directory to its path.
NB: For those who wonder, the sample command used here (to select a folder) is FOLDERBROWSE.EXE. I found it on the web site f2ko.de (http://f2ko.de/en/cmd.php).
If anyone has a better solution for that kind of commands accessible through a complex path, I will be very glad to hear of it.
Gilles
Just use the result from the FOR command. For example (inside a batch file):
for /F "delims=" %%I in ('dir /b /a-d /od FILESA*') do (echo %%I)
You can use the %%I as the value you want. Just like this: %%I.
And in advance the %%I does not have any spaces or CR characters and can be used for comparisons!!
If you're looking for the solution provided in Using the result of a command as an argument in bash?
then here is the code:
#echo off
if not "%1"=="" goto get_basename_pwd
for /f "delims=X" %%i in ('cd') do call %0 %%i
for /f "delims=X" %%i in ('dir /o:d /b') do echo %%i>>%filename%.txt
goto end
:get_basename_pwd
set filename=%~n1
:end
This will call itself with the result of the CD command, same as pwd.
String extraction on parameters will return the filename/folder.
Get the contents of this folder and append to the filename.txt
[Credits]: Thanks to all the other answers and some digging on the Windows XP commands page.
#echo off
ver | find "6.1." > nul
if %ERRORLEVEL% == 0 (
echo Win7
for /f "delims=" %%a in ('DIR "C:\Program Files\Microsoft Office\*Outlook.EXE" /B /P /S') do call set findoutlook=%%a
%findoutlook%
)
ver | find "5.1." > nul
if %ERRORLEVEL% == 0 (
echo WinXP
for /f "delims=" %%a in ('DIR "C:\Program Files\Microsoft Office\*Outlook.EXE" /B /P /S') do call set findoutlook=%%a
%findoutlook%
)
echo Outlook dir: %findoutlook%
"%findoutlook%"
You can capture all output in one variable, but the lines will be separated by a character of your choice (# in the example below) instead of an actual CR-LF.
#echo off
setlocal EnableDelayedExpansion
for /f "delims=" %%i in ('dir /b') do (
if "!DIR!"=="" (set DIR=%%i) else (set DIR=!DIR!#%%i)
)
echo directory contains:
echo %DIR%
Second version, if you need to print the contents out line-by-line. This takes advanted of the fact that there won't be duplicate lines of output from "dir /b", so it may not work in the general case.
#echo off
setlocal EnableDelayedExpansion
set count=0
for /f "delims=" %%i in ('dir /b') do (
if "!DIR!"=="" (set DIR=%%i) else (set DIR=!DIR!#%%i)
set /a count = !count! + 1
)
echo directory contains:
echo %DIR%
for /l %%c in (1,1,%count%) do (
for /f "delims=#" %%i in ("!DIR!") do (
echo %%i
set DIR=!DIR:%%i=!
)
)
#echo off
setlocal EnableDelayedExpansion
FOR /F "tokens=1 delims= " %%i IN ('echo hola') DO (
set TXT=%%i
)
echo 'TXT: %TXT%'
the result is 'TXT: hola'
You should use the for command, here is an example:
#echo off
rem Commands go here
exit /b
:output
for /f "tokens=* useback" %%a in (`%~1`) do set "output=%%a"
and you can use call :output "Command goes here" then the output will be in the %output% variable.
Note: If you have a command output that is multiline, this tool will set the output to the last line of your multiline command.
Please refer to this http://technet.microsoft.com/en-us/library/bb490982.aspx which explains what you can do with command output.

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