MS-DOS batch script: assignment operation - batch-file

Question

I am referring to below threat Batch files: How to read a file?. For retrieving the line by line from a text file. I am using the below script:
#echo off
SETLOCAL DisableDelayedExpansion
FOR /F "usebackq delims=" %%a in (`"findstr /n ^^ paths.txt"`) do (
set "var=%%a"
SETLOCAL EnableDelayedExpansion
set "var=!var:*:=!"
echo !var!
ENDLOCAL
)
Code is working fine! The values in !var! can not assign to any variable. :( I struct there, Please anyone help to read line by line and I wish to assign to some variable and want to manipulate that variable. Please help to solve this situation.
Update:
#ECHO off
CLS
SET PROJ_DIR=D:\workspace\proj
SET PROMO_DIR=D:\TEST
SET SOURCE_CODE=\Source Code
SETLOCAL DisableDelayedExpansion
for /f %%a in (paths.txt) do (
SET "var=%%a"
SETLOCAL EnableDelayedExpansion
set "var=!var:*:=!"
set FILE_PATH=!var://www.domain.com/path/dir=!
SET FILE_PATH=!FILE_PATH:/=\!
SET PROMO_FILE_PATH=!PROMO_DIR!!SOURCE_CODE!!FILE_PATH!
FOR %%i IN ("!PROMO_FILE_PATH!") DO SET FOLDER_PATH=%%~dpi
FOR %%i IN ("!PROMO_FILE_PATH!") DO SET FILE_NAME=%%~nxi
IF EXIST "!FOLDER_PATH!" GOTO F3
MKDIR "!FOLDER_PATH!"
:F3
IF NOT EXIST "!PROJ_DIR!!FILE_PATH!" GOTO F4
COPY "!PROJ_DIR!!FILE_PATH!" "!FOLDER_PATH!"
:F4
ECHO Cannot find the file under "!PROJ_DIR!!FILE_PATH!"
ENDLOCAL
)
SET CLOSE_CONFIRM=
SET /P CLOSE_CONFIRM=Press any key to close the window...%=%
paths.txt
//www.domain.com/path/dir/dir1/dir2/file1.txt
//www.domain.com/path/dir/dir1/dir2/file2.txt
//www.domain.com/path/dir/dir1/dir2/file3.txt
//www.domain.com/path/dir/dir1/dir2/file4.txt
//www.domain.com/path/dir/dir1/dir3/file1.txt
Command Output
1 file(s) copied.
Cannot find the file under "D:\workspace\proj\dir1\dir2\file1.txt"
1 file(s) copied.
Cannot find the file under "D:\workspace\proj\dir1\dir2\file2.txt"
Press any key to close the window...
thanks..

Answer 1

The key is the delayed expansion, expand your variables inside of parenthesis always with ! not with %.
A sample that changes X with Y
#echo off
SETLOCAL DisableDelayedExpansion
FOR /F "usebackq delims=" %%a in (`"findstr /n ^^ paths.txt"`) do (
set "var=%%a"
SETLOCAL EnableDelayedExpansion
set "var=!var:*:=!"
set "myVar=!var!"
set "myVar=!myVar:X=Y!"
echo X replaced with Y =!myVar!
ENDLOCAL
)
In your updated version the goto :label stops the for-loop immediatly
Better rewrite it to IF-Blocks
IF NOT EXIST "!FOLDER_PATH!" (
MKDIR "!FOLDER_PATH!"
)
IF EXIST "!PROJ_DIR!!FILE_PATH!" (
COPY "!PROJ_DIR!!FILE_PATH!" "!FOLDER_PATH!"
) ELSE
(
ECHO Cannot find the file under "!PROJ_DIR!!FILE_PATH!"
)

Answer 2

The other answers here cover the tricky bits of delayed expansion in this code. I want to add that you can often avoid most delayed expansion problems by rolling the parentheses out into a subroutine.
FOR /F "usebackq delims=" %%a in (`"findstr /n ^^ paths.txt"`) do call :HandlePath %%a
goto :eof
================
:HandlePath
set "var=%*"
set "var=%var:*:=%"
echo %var%
goto :eof
I find this code easier to maintain because each line is parsed an executed exactly when you would expect.

Answer 3

If you want to read each line and manipulate it:
SETLOCAL EnableDelayedExpansion
FOR /F "tokens=*" %%a IN (paths.txt) DO (
set var=%%a
ECHO %var%
PAUSE
)
ENDLOCAL
If you are trying to search a string from a file and manipulate it:
SETLOCAL EnableDelayedExpansion
FOR /F "tokens=* usebackq" %%a IN (`FIND /I 'string to search for' "C:\folder\paths.txt"`) DO (
set var=%%a
ECHO %var%
PAUSE
)
ENDLOCAL
If you are trying to search a string and manipulate each word in the string:
SETLOCAL EnableDelayedExpansion
FOR /F "usebackq tokens=1-999 delims= " %%a IN (`FIND /I 'string to search for' "C:\folder\paths.txt"`) DO (
REM %%a = first word %%b = second word etc. through the alphabet
set var1=%%a%%b%%c
set var2=%%d
ser var3=%%e
ECHO %var1% %var2% %var3%
PAUSE
)
ENDLOCAL

Answer 4

This works for me:
#echo off
SETLOCAL EnableDelayedExpansion
FOR /F "usebackq delims=" %%a in (`"findstr /n ^^ paths.txt"`) do (
set var=%%a
set var=!var:*:=!
echo !var!
)
ENDLOCAL