How to get filename in variable inside loop? - windows

I want to loop through all .h files in the current directory and call a batch function for the corresponding .cpp file. Actually I had it working already, but when I tried to use local variables I get some strange output.
SETLOCAL
for /R %%f in (*.h) do (
SET header=%f%
ECHO header=%header%
SET source=%%~df%%~pf%%~nf.cpp
ECHO source=%source%
)
I get this output:
SETLOCAL
C:\WorkingDirectory>(
SET header=
ECHO header=
SET source=C:\WorkingDirectory\SomeFile.cpp
ECHO source=
)
header=
source=
Why is %%~df%%~pf%%~nf.cpp correctly expanded, but ECHO %source% prints nothing? How can I correctly SET header=%f%?

1) The variable you are accessing is not accessed with %f% but %%f
2) As #npocmaka already mentioned as a comment DelayedExpansion is needed as in batch every block of closed parenthesis is parsed at once when using the usual %. To get rid of that problem, add setlocal EnableDelayedExpansion to your script after #echo off and change %header% to !header!. The same goes for %source%, but not so for the loop variable %%f!
SETLOCAL EnableDelayedExpansion
for %%f in (*.h) do (
SET header=%%~ff
ECHO header=!header!
SET source=%%~df%%~pf%%~nf.cpp
ECHO source=!source!
)

Related

How to process pathnames with ! within an for /F loop?

In a complex batch file I want to read in files with paths, among other things, to read them into a variable one after the other separated by spaces.
This works with the following code so far quite well - but only if the path does not contain an exclamation mark.
Even using the setlocal command (enabledelayedexpansion / disabledelayedexpansion) I did not succeed in processing exclamation marks.
Does anyone here have a clever idea to the problem?
The following example batch creates a text file in the current directory and then reads it in a for /F loop.
At the end all three paths from the text file should be in the variable %Output%. But with the exclamation mark.
#echo off
setlocal enabledelayedexpansion
echo This is an example^^! > "textfile.txt"
echo This is a second example^^! >> "textfile.txt"
echo And this line have an ^^! exclamation mark in the middle >> "textfile.txt"
for /F "usebackq tokens=* delims=" %%a in (textfile.txt) do (
set "Record=%%a"
set "Output=!Output!!Record! - "
)
)
echo %Output%
echo !Output!
endlocal
The Output is like this:
This is an example - This is a second example - And this line have an exclamation mark in the middle
But should be like this:
This is an example! - This is a second example! - And this line have an ! exclamation mark in the middle
It is advisable not using delayed variable expansion on processing files and directories, lines in a text file, strings not defined by the batch file itself, or output captured from the execution of a program or a command line. If it is for some reasons necessary to make use of delayed variable expansion inside a FOR loop, there should be first assigned the file/directory name, the line, or the string to process to an environment variable while delayed expansion is disabled and then enable delayed expansion temporary inside the FOR loop.
Here is a batch file demo which can be simply run from within a command prompt window or by double clicking on the batch file. It creates several files for demonstration in the directory for temporary files, but deletes them all before exiting.
#echo off
setlocal EnableExtensions DisableDelayedExpansion
echo This is an example!> "%TEMP%\TextFile.tmp"
echo This is a second example!>> "%TEMP%\TextFile.tmp"
echo And this line has an exclamation mark ! in the middle.>> "%TEMP%\TextFile.tmp"
set "Output="
(for /F usebackq^ delims^=^ eol^= %%I in ("%TEMP%\TextFile.tmp") do set "Line=%%I" & call :ConcatenateLines) & goto ContinueDemo
:ConcatenateLines
set "Output=%Output% - %Line%" & goto :EOF
:ContinueDemo
cls
echo/
echo All lines concatenated are:
echo/
echo %Output:~3%
set "Output="
del "%TEMP%\TextFile.tmp"
echo File with name ".Linux hidden file!">"%TEMP%\.Linux hidden file!"
echo File with name "A simple test!">"%TEMP%\A simple test!"
echo File with name " 100%% Development & 'Test' (!).tmp">"%TEMP%\ 100%% Development & 'Test(!)'.tmp"
echo/
echo Files with ! are:
echo/
for /F "eol=| tokens=* delims=" %%I in ('dir "%TEMP%\*!*" /A-D /B /ON 2^>nul') do (
set "NameFile=%%I"
set "FileName=%%~nI"
set "FileExtension=%%~xI"
set "FullName=%TEMP%\%%I"
setlocal EnableDelayedExpansion
if defined FileName (
if defined FileExtension (
echo File with ext. !FileExtension:~1!: !NameFile!
) else (
echo Extensionless file: !NameFile!
)
) else echo Extensionless file: !NameFile!
del "!FullName!"
endlocal
)
endlocal
echo/
#setlocal EnableExtensions EnableDelayedExpansion & for /F "tokens=1,2" %%G in ("!CMDCMDLINE!") do #endlocal & if /I "%%~nG" == "cmd" if /I "%%~H" == "/c" set /P "=Press any key to exit the demo . . . "<nul & pause >nul
The output of this batch file is:
All lines concatenated are:
This is an example! - This is a second example! - And this line has an exclamation mark ! in the middle.
Files with ! are:
File with ext. tmp: 100% Development & 'Test(!)'.tmp
Extensionless file: .Linux hidden file!
Extensionless file: A simple test!
The text file example with concatenating lines makes use of a subroutine called from within the FOR loop processing the lines in the text file. The syntax used here is for maximum performance by getting the subroutine as near as possible to the FOR command line. That is important if the FOR loop has to process hundreds or even thousands of items.
The example processing file names enables and disables delayed expansion inside the FOR loop after having assigned all parts of the currently processed file to environment variables. It could be useful to reduce the list of environment variables before processing thousands of files for a better performance on using this method.
Another method is shown in Magoo´s answer using the command CALL to get a command line with referenced environment variables (re)defined inside the loop parsed a second time. I used that method also in the past quite often, but don't that anymore as it is not fail-safe and not efficient. call set results in searching by cmd.exe in current directory and next in all directories of environment variable PATH for a file with name set and a file extension of environment variable PATHEXT. So it results in lots of file system accesses in the background on each iteration of the FOR loop and if there is by chance a file set.exe, set.bat, set.cmd, etc. found by cmd.exe somewhere, the batch file does not work anymore as expected because of running the executable or calling the batch file instead of the (re)definition of the environment variable.
The following answers written by me could be also helpful:
How to read and print contents of text file line by line?
It explains in full details how to process all lines of a text file.
How to pass environment variables as parameters by reference to another batch file?
It explains in full details what the commands SETLOCAL and ENDLOCAL do.
How to pass a command that may contain special characters (such as % or !) inside a variable to a for /f loop?
This is an example of a batch file designed to process video files with any valid file name on any Windows computer very efficient, safe and secure with full explanation.
Well, the main trick is to enable delayed expansion only when it is actually needed and to disable it otherwise. Since you are accumulating multiple strings in a single variable inside of a loop, it becomes a bit more difficult, because you should have delayed expansion disabled during expansion of for meta-variables (like %%a), but enabled when joining the string, leading to setlocal and endlocal statements inside of the loop. The major purpose of these commands is environment localisation, hence any variable changes become lost past endlocal, so a method of tansfering the value beyond endlocal is required, which is incorporated in the following code:
#echo off
setlocal EnableExtensions DisableDelayedExpansion
rem /* At this point delayed expansion is disabled, so there is no need to
rem escape exclamation marks; moreover a redirected block prevents
rem superfluous file close/reopen operations, and there is no more
rem trailing space written to the file (as in your original approach): */
> "textfile.txt" (
echo This is an example!
echo This is a second example!
echo And this line have an ! exclamation mark in the middle
)
rem // Let us initialise the output variable:
set "Output= - "
rem // Using `usebackq` only makes sense when you want to quote a file path:
for /F "usebackq tokens=* delims=" %%a in ("textfile.txt") do (
rem // Remember that delayed expansion is still disabled at this point:
set "Record=%%a"
rem // For concatenation we need delayed expansion to be enabled:
setlocal EnableDelayedExpansion
set "Output=!Output!!Record! - "
rem /* We need to terminate the environment localisation of `setlocal`
rem inside of the loop, but we would lose any changes in `Output`;
rem therefore let us (mis-)use `for /F`, which is iterated once: */
for /F "delims=" %%b in ("!Output!") do endlocal & set "Output=%%b"
rem /* An often used method to transfer a variable beyond `endlocal` is
rem the line `endlocal & set "Output=%Output%`, but this only works
rem outside of a parenthesised block because of percent expansion. */
)
rem /* Echo out text with delayed expansion enabled is the only safe way;
rem surrounding separators ` - ` are going to be removed; since `Output`
rem was initialised with something non-empty, we do not even need to skip
rem sub-string expansion for the problematic case of an empty string: */
setlocal EnableDelayedExpansion
echo(!Output:~3,-3!
endlocal
endlocal
exit /B
Pew. I finally got it to work.
It works via a workaround using a second text file.
Not pretty, not performant, but it works and is sufficient for my purposes.
#Magoo, thanks for your post.
This is my solution:
#echo off
setlocal enableextensions enabledelayedexpansion
echo This is an example^^!> "textfile.txt"
echo This is a second example^^!>> "textfile.txt"
echo And this line have an ^^! exclamation mark in the middle>> "textfile.txt"
echo.
echo Content of the textfile:
type "textfile.txt"
set output=
del "textfile2.txt" 1> nul 2>&1
setlocal disabledelayedexpansion
for /f "usebackq tokens=* delims=" %%a IN ("textfile.txt") do (
rem Write each line without a newline character into a new text file
echo|set /p "dummy=%%a, ">>"textfile2.txt"
)
endlocal
rem Loading the content of the new text file into the variable
set /p output=<"textfile2.txt"
del "textfile2.txt" 1> nul 2>&1
echo.
echo --------------------------------------------
echo Content of the variable:
set out
endlocal
The output looks like this:
Content of the textfile:
This is an example!
This is a second example!
And this line have an ! exclamation mark in the middle
--------------------------------------------
Content of the variable:
output=This is an example!, This is a second example!, And this line have an ! exclamation mark in the middle,
It's delayedexpansion mode that appears to raise this problem.
#ECHO OFF
setlocal enabledelayedexpansion
echo This is an example^^^! > "textfile.txt"
echo This is a second example^^^! >> "textfile.txt"
echo And this line have an ^^^! exclamation mark in the middle >> "textfile.txt"
TYPE "textfile.txt"
SETLOCAL disabledelayedexpansion
for /F "usebackq tokens=* delims=" %%a in (textfile.txt) do (
set "Record=%%a"
CALL set "Output2=%%Output2%%%%record%% - "
CALL set "Output=%%Output%%%%a - "
SET out
)
)
endlocal&SET "output=%output%"
echo %Output%
echo !Output!
SET out
I've no doubt that with delayedexpansion off, there would be the same problem with %. Just special characters, I suppose.
Note that with endlocal&SET "output=%output%", the set is executed in delayedexpansion mode.

Keep variable after endlocal in Batch

I have a folder structure, which is like for example C:\Temp\ and there are a lot of folder and file, and within each folder there are a "callme.bat". I would like to create a so called main.bat which is one after another call the callme files within the main' window. But there is a problem, within the callme files are some echo which contains "!" mark what make a problem for me.
I realized the problem with the setlocal-endlocal combo, because the batch scrip wants to interpret the message within the "!" marks, so I must use endlocal, but if I did I not able to run the callme bats.
callme.bat
#echo off
echo !!! hidden message !!! not hidden message
pause
main.bat variant 1
#echo off
setlocal enabledelayedexpansion
set PATH=C:\Temp
for /F %%x in ('dir /B/A:D %PATH%') do (
set CURR_DIR=%PATH%\%%x
set ACTUAL_BATCH=!CURR_DIR!\callme.bat
echo !ACTUAL_BATCH!
call !ACTUAL_BATCH!
pause
)
pause
exit
main.bat variant 2
#echo off
set PATH=C:\Temp
for /F %%x in ('dir /B/A:D %PATH%') do (
setlocal enabledelayedexpansion
set CURR_DIR=%PATH%\%%x
set ACTUAL_BATCH=!CURR_DIR!\callme.bat
echo !ACTUAL_BATCH!
ENDLOCAL & SET VAR=!ACTUAL_BATCH!
echo %VAR%
pause
)
pause
exit
main.bat variant 3
#echo off
set PATH=C:\Temp
for /F %%x in ('dir /B/A:D %PATH%') do (
setlocal enabledelayedexpansion
set CURR_DIR=%PATH%\%%x
set ACTUAL_BATCH=!CURR_DIR!\callme.bat
echo !ACTUAL_BATCH!
REM source: https://stackoverflow.com/questions/3262287/make-an-environment-variable-survive-endlocal
for /f "delims=" %%A in (""!ACTUAL_BATCH!"") do endlocal & set "VAR=%%~A"
echo %VAR%
call %VAR%
pause
)
pause
exit
So I don't know what to do. Anyone has an idea?
variant 1's output:
C:\Temp\1\callme.bat
not hidden message
C:\Temp\2\callme.bat
not hidden message
variant 2-3's output:
C:\Temp\1\callme.bat
ECHO is off.
C:\Temp\2\callme.bat
ECHO is off.
TL;DR
ENDLOCAL&set "varname=%sourcevarname%"
probably, where varname is the variablename to set and sourcevarname is the variable whose value is to be assigned to varname - and they CAN be the same name, even if the statement appears logically null - it's exporting the variable from within the setlocal/endlocal block.
Key point: MUST be on one physical line and may be repeated if necessary (ie
ENDLOCAL&set "varname=%sourcevarname%"&set "varname2=%sourcevarname2%"
So
ENDLOCAL&set "fred=%fred%"&set "bill=%george%"
is perfectly valid, to set the value of fred outside the setlocal/endlocal bracket to its final value inside and of billoutside to the final value of george inside.
Some points about your code:
Never use PATH as a variable name, as it destroys the PATH variable for searching executable files.
Use the extended SET syntax set "varname=content" to avoid problems with trainling spaces.
You only need to disable the delayed expansion mode by using setlocal DisableDelayedExpansion
#echo off
setlocal EnableDelayedExpansion
set MY_PATH=C:\Temp
for /F %%x in ('dir /B/A:D %PATH%') do (
set "CURR_DIR=%MY_PATH%\%%x"
set "ACTUAL_BATCH=!CURR_DIR!\callme.bat"
call :execute ACTUAL_BATCH
pause
)
pause
exit /b
:execute ACTUAL_BATCH
set "batFile=!%~1!"
echo Calling !batFile!
setlocal DisableDelayedExpansion
call %batFile%
endlocal
exit /b

Windows 7 Batch File for loop

In both cases the directory contains three files named test1.txt, test2.txt, test3.txt
Can someone explain why this works:
echo off
set CP=
for %%f in (*.txt) do (
call :concat %%f
)
echo %CP%
:concat
set CP=%CP%;%1
output:
C:\test>test
C:\test>echo off
;test1.txt;test2.txt;test3.txt
C:\test>
But this does not:
echo off
set CP=
for %%f in (*.txt) do (
set CP=set CP=%CP%;%%f
)
echo %CP%
output:
C:\test>test
C:\test>echo off
;test3.txt
C:\test>
It has to do with Delayed Expansion.
For example, this will work just like your first example:
echo off
SETLOCAL EnableDelayedExpansion
set CP=
for %%f in (*.txt) do (
set CP=!CP!;%%f
)
echo %CP%
ENDLOCAL
When Delayed Expansion is enabled then variables surrounded with ! are evaluated on each iteration instead of only the first time when the loop is parsed (which is how variables surrounded with % are parsed).
Your first example works because the processing is done in a CALL statement which passes control to another segment of the batch file which is technically outside the loop so it is parsed individually each time it is executed.

Copy a variable from a for loop in another variable in a batch file

I need to copy a variable from a for loop ( %%i ) in another variable.
I've tried:
set temp=%%i
but when I want to use the %temp% variable I receive the error: Missing operand.
echo %%i displays my desired value.
Also I've tried:
set temp=%%~ni
but is the same error: Missing operand.
Thanks.
You need to set Delayed Expansion.
Example:
setlocal enabledelayedexpansion
for /F %%a in (stations.tmp) do (
set tmp= %%a
echo !tmp! >> stations.cfg
)

Concatenate file paths to variable in batch script

I have a script that I've put together that should copy the list of files to a variable but the only thing I receive is the last file. In other words, when I echo the variable in my for loop, I see 20 or so files but only the last one gets copied to my variable. How can I get them all to copy correctly?
I am using Windows 7.
#echo off
setlocal enabledelayedexpansion enableextensions
for /r %%x in (*) do (
echo %%x
SET PATH_VALUE=%%x;%PATH_VALUE%
)
One way is to use delayed expansion. You've enabled it – half the job done. Now you only want to use it. Replace the %s around PATH_VALUE with !s and you are done:
#echo off
setlocal enabledelayedexpansion enableextensions
for /r %%x in (*) do (
echo %%x
SET PATH_VALUE=%%x;!PATH_VALUE!
)

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