#echo off
(for /f "skip=1 tokens=3,5,11" %%a in (Data.txt) do (if /i "%%c"=="%1" (if %%b==%2 echo %%a))
echo EXIT
)|Sum.exe
I'm trying to write a simple batch script that would take the .txt file with columns of data (Data.txt), find some values using 'if' and redirect all found values to stdin input of "Sum.exe".
"EXIT" is also redirected as it means that there's no more input to be given.
When I run above code first found value is printed in console and then "The process tried to write to a nonexistent pipe" message error is printed multiple times. Therefore echo EXIT somehow must be messing up with |Sum.exe. How to properly redirect both for and echo Exit into Sum?
EDIT:
Ok, so here's the input part of the Sum program (written in c++)
std::string a;
while (a != "EXIT")
{
std::cin >> a;
if (isNumber(a))
add(sum, std::stoi(a));
}
I added cout to see whether the data was being processed and it seems that the commands in batch script were treted as input aswell.
My first suggestion would be procedure call: call :PROCEDURE. But the call doesn't work with pipe redirection.
For example call :PROCEDURE | SORT return error: Invalid attempt to call batch label outside of batch script.
So I suggest to use input parameter as switch flag to call self batch. For example it would be third parameter: %3. Batch calls itself while third parameter equals x.
So I made this code
#echo off
if "%3"=="x" (%~nx0 %1 %2|sort )& GOTO :EOF
for /f "skip=1 tokens=3,5,11" %%a in (Data.txt) do (
if /i "%%c"=="%1" (if %%b==%2 echo %%a)
echo EXIT
)
I use sort.exe utility in my example. Change it to your sum.exe
To call batch-file use syntax: my_batch.cmd [value11] [value5] x
P.S. I think you do not need word EXIT in output but I left it in example code.
I want to access STDIN from inside a batch file after some other commands. I know that the first command in a .BAT file receives STDIN but I want to first run some other commands and then capture STDIN. I also want this to work with streamed STDIN i.e. it is not acceptable to capture STDIN to a file at the start with (see workaround below).
Now, I understand that CON is the "file" representing STDIN and that TYPE CON would output (echo) STDIN. This does not seem to work at all inside a batch file. Indeed, it appears not to represent STDIN but user/host input by keyboard.
test.bat
TYPE CON > output.txt
Test run:
C:>TYPE myfile.txt | test.bat
Expected result: myfile.txt is copied into output.txt.
Actual result: The batch waits for user input (ignores what is piped to it) and writes user input typed on the keyboard to output.txt.
Workaround
As a workaround: the following test.bat works but does not support streamed input (e.g. from a tail command):
findstr "^" STDIN.txt
:: I can now run some other commands
:: And finally access my STDIN via STDIN.txt
TYPE STDIN.txt | AWK /e/ > output.txt
UPDATE: Back Story:
I have a neat CMD which uses powershell to download (via HTTP) an arbitrary .ps1 script (like a package manager would) and execute it on the fly. If I call REMEXEC.bat mymodule foo bar it loads and executes mymodule.ps1 with the parameters foo and bar.
This works wonderfully for every scenario except piped, streamed input. Using the findstr "^" works for piped input but not for an open stream. Using say AWK /.*/ as the first line of my BAT gets me that streamed input but just pushes the problem down the road.
Ultimately I want a something.bat which looks like this (pseudocode):
downloadPSModule( "http://myrepo.com/modules/%1.ps1" )
STDIN | executePSModule %2 %3 %4
The catch 22 is that downloadPSModule happens BEFORE executePSModule and thus has no access to STDIN (a privelege reserved for the first line of a BAT).
If you need to retrieve input from console or isolate reading from the stdin stream to not consume piped data, I would try directly reading from console with something like
#echo off
setlocal enableextensions disabledelayedexpansion
rem Part that reads from console, not piped input
< con (
set "data="
set /p "data=Type something: "
)
echo(
echo You have typed: [%data%]
echo(
rem Part that reads piped input
find /v ""
When executed
W:\>type test.cmd | test.cmd
Type something: this is a test
You have typed: [this is a test]
#echo off
setlocal enableextensions disabledelayedexpansion
rem Part that reads from console, not piped input
< con (
set "data="
set /p "data=Type something: "
)
echo(
echo You have typed: [%data%]
echo(
rem Part that reads piped input
find /v ""
I'm trying to do a Windows batch file that excecute a command and pass to it a flow param that is received as a parameter of the batch file, then I need to get the output of this execution and do something with it before sending it to the batch output (cuting the output to get the first character only).
This is what I have so far:
for /f %%i in ('"C:\Program Files (x86)\JAM Software\SpamAssassin for Windows\spamc.exe" < %1') do set RES2 = %%i
ECHO %RES2~0,1%
But it is not working as I expect. Thanks for the help.
for /f %%i in (
'"C:\Program Files (x86)\JAM Software\SpamAssassin for Windows\spamc.exe" ^< %1'
) do set RES2=%%i
ECHO %RES2:~0,1%
There are three changes in your code. The colon in the echo line (needed, it is part of the sintax), the escaped redirection and the spaces removed around the equal sign in the set line. With spaces, the variable name contains a space and the value inside the variable also have a space in it (and it will be the first, so the later echo command will fail)
I was looking at redirecting handles in batch, when I noticed this:
Here is the link
It mentions that handles 3-9 are undefined and can be defined by a program. Now I've read about doing this in C#, but I wondered if this was possible in cmd/batch - and if it is, what are its limitations/use.
If it is not possible in cmd, how would I go about using this, and could it be a solution to outputting data to the screen and redirecting it to a file at the same time (a problem which has not been able to be done legitimately at the same time).
Thanks, Mona.
A Batch file is limited to manage just two files: STDIN for input (SET /P) operations, and STDOUT for output (ECHO, etc.) operations; however, we could have access to more than one input and output files in a Batch file. How to do that? In a relatively easy way: just connect the additional files to unused handles (3-9) and use the appropiate handle in the input (SET /P <&#) or output (ECHO >&#) commands.
The Batch file below merge the lines of 3 input files into one output file with larger lines:
#echo off
setlocal EnableDelayedExpansion
3<input2.txt 4<input3.txt (
for /F "delims=" %%a in (input1.txt) do (
set line=
rem Read from input2.txt (and write line from input1 to output.txt):
set /P line=%%a <&3
rem Read from input3.txt (and write line from input2 to output.txt):
set /P line=!line! <&4
rem Write line from input3 to output.txt:
echo(!line!
)
) >output.txt
The same method may be used to generate several output files.
See: Access to SEVERAL files via Standard Handles
And a more technical explanation here
This question already has answers here:
Set output of a command as a variable (with pipes) [duplicate]
(6 answers)
Closed 7 years ago.
I need to run a simple find command and redirect the output to a variable in a Windows Batch File.
I have tried this:
set file=ls|find ".txt"
echo %file%
But it does not work.
If I run this command it works without problems:
set file=test.txt
echo %file%
So obviously my command output is not being set to my variable. Can anyone help? Thanks
I just find out how to use commands with pipes in it, here's my command (that extracts the head revision of an svn repo) :
SET SVN_INFO_CMD=svn info http://mySvnRepo/MyProjects
FOR /f "tokens=1 delims=" %%i IN ('%SVN_INFO_CMD% ^| find "Revision"') DO echo %%i
First of all, what you seem to expect from your question isn't even possible in UNIX shells. How should the shell know that ls|find foo is a command and test.txt is not? What to execute here? That's why UNIX shells have the backtick for such things. Anyway, I digress.
You can't set environment variables to multi-line strings from the shell. So we now have a problem because the output of ls wouldn't quite fit.
What you really want here, though, is a list of all text files, right? Depending on what you need it's very easy to do. The main part in all of these examples is the for loop, iterating over a set of files.
If you just need to do an action for every text file:
for %%i in (*.txt) do echo Doing something with "%%i"
This even works for file names with spaces and it won't erroneously catch files that just have a .txt in the middle of their name, such as foo.txt.bar. Just to point out that your approach isn't as pretty as you'd like it to be.
Anyway, if you want a list of files you can use a little trick to create arrays, or something like that:
setlocal enabledelayedexpansion
set N=0
for %%i in (*.txt) do (
set Files[!N!]=%%i
set /a N+=1
)
After this you will have a number of environment variables, named Files[0], Files[1], etc. each one containing a single file name. You can loop over that with
for /l %%x in (1,1,%N%) do echo.!Files[%%x]!
(Note that we output a superfluous new line here, we could remove that but takes one more line of code :-))
Then you can build a really long line of file names, if you wish. You might recognize the pattern:
setlocal enabledelayedexpansion
set Files=
for %%i in (*.txt) do set Files=!Files! "%%i"
Now we have a really long line with file names. Use it for whatever you wish. This is sometimes handy for passing a bunch of files to another program.
Keep in mind though, that the maximum line length for batch files is around 8190 characters. So that puts a limit on the number of things you can have in a single line. And yes, enumerating a whole bunch of files in a single line might overflow here.
Back to the original point, that batch files have no way of capturing a command output. Others have noted it before. You can use for /f for this purpose:
for /f %%i in ('dir /b') do ...
This will iterate over the lines returned by the command, tokenizing them along the way. Not quite as handy maybe as backticks but close enough and sufficient for most puposes.
By default the tokens are broken up at whitespace, so if you got a file name "Foo bar" then suddenly you would have only "Foo" in %%i and "bar" in %%j. It can be confusing and such things are the main reason why you don't ever want to use for /f just to get a file listing.
You can also use backticks instead of apostrophes if that clashes with some program arguments:
for /f "usebackq" %%i in (`echo I can write 'apostrophes'`) do ...
Note that this also tokenizes. There are some more options you can give. They are detailed in the help for command.
set command has /p option that tells it to read a value from standard input. Unfortunately, it does not support piping into it, but it supports reading a value from a first line of existing file.
So, to set your variable to the name of a first *.txt file, you could do the following:
dir /b *.txt > filename.tmp
set /p file=< filename.tmp
del /q filename.tmp
It is important not to add a space before or even after =.
P. S. No fors, no tokens.
Here's a batch file which will return the last item output by find:
#echo off
ls | find ".txt" > %temp%\temp.txt
for /f %%i in (%temp%\temp.txt) do set file=%%i
del %temp%\temp.txt
echo %file%
for has a syntax for parsing command output, for /f "usebackq", but it cannot handle pipes in the command, so I've redirected output to a temporary location.
I strongly recommend, given that you have access to ls, that you consider using a better batch language, such as bash or even an scripting language like python or ruby. Even bash would be a 20x improvement over cmd scripting.
The short answer is: Don't!
A windows shell env var can hold a max of 32 Kb and it isn't safe to save output from programs in them.
That's why you can't. In batch script you must adopt another programming style. If you need all of the output
from the program then save it to file. If you only need to check for certain properties then pipe the output into
a program that does the checking and use the errorlevel mechanism:
#echo off
type somefile.txt | find "somestring" >nul
if %errorlevel% EQU 1 echo Sorry, not found!
REM Alternatively:
if errorlevel 1 echo Sorry, not found!
However, it's more elegant to use the logical operators Perl style:
#echo off
(type somefile.txt | find "somestring" >nul) || echo Sorry, not found!
It's not available in DOS, but in the Windows console, there is the for command. Just type 'help for' at a command prompt to see all of the options. To set a single variable you can use this:
for /f %%i in ('find .txt') do set file=%%i
Note this will only work for the first line returned from 'find .txt' because windows only expands variable once by default. You'll have to enable delayed expansion as shown here.
what you are essentially doing is listing out .txt files. With that, you can use a for loop to over dir cmd
eg
for /f "tokens=*" %%i in ('dir /b *.txt') do set file=%%i
or if you prefer using your ls, there's no need to pipe to find.
for /f "tokens=*" %%i in ('ls *.txt') do set file=%%i
Example of setting a variable from command output:
FOR /F "usebackq" %%Z IN ( `C:\cygwin\bin\cygpath "C:\scripts\sample.sh"` ) DO SET BASH_SCRIPT=%%Z
c:\cygwin\bin\bash -c '. ~/.bashrc ; %BASH_SCRIPT%'
Also, note that if you want to test out the FOR command in a DOS shell, then you need only use %Z instead of %%Z, otherwise it will complain with the following error:
%%Z was unexpected at this time.