如何将命令结果批量存储到变量中？

Question

I'm tryng to make a .bat file to add blank lines to a text file, based on the amount of lines that match a condition. This is what a have:

@echo
SET /a maxLineas = 50
SET cantLineasDetalle="type texto.txt | find /i /c "D01" "
SET /a cantLineasAgregar = %maxLineas% - %cantLineasDetalle%

:loop
echo. >> texto.txt
set /a cantLineasAgregar-=1
if %cantLineasAgregar% GTR 0 goto loop

The trouble is that var "cantLineasDetalle" isn't storing the value that I want it to do.

How do I asign the result of the execution of 'type texto.txt | find /i /c "D01"' to a variable?

Thanks in advance, Esteban.

Answer 1

As the previous answer indicated, you use a FOR /F loop to store the results of a command into a variable.

find "search" <file can be significantly more efficient than type file | find "search" type file | find "search" if the file is large.

When executed within a FOR /F IN() clause, all special characters must be either quoted or escaped. In your case the pipe will need to be escaped, or if you take my suggestion, the < will need to be escaped.

echo. >>file echo. >>file will append a line with a space to the file. Also, it is safer to use echo( instead of echo. , but you will probably never run into a problem with echo. To get a blank line without a space use echo(>>file

When using SET /A to do math, you can refer to variables directly without enclosing them in percents. It also works with the percents.

Lastly, it is much more efficient to append the lines within a FOR /L loop instead of using a GOTO loop.

@echo off
set /a maxLineas=50
for /f %%N in('find /i /c:"D01" ^<texto.txt') do set /a cantLineasDetalle=%%N
set /a cantLineasAgregar=maxLineas-cantLineasDetalle
for /l %%N in (1 1 %cantLineasAgregar%) do echo(>>texto.txt

The entire script could be compressed to the following (maxLineas is now 0 based)

@echo off
set /a maxLineas=50-1
for /f %%N in('find /i /c:"D01" ^<texto.txt') do for /l %%I in (%%N 1 %maxLineas%) do echo(>>texto.txt

Answer 2

/ f %% i在（'type texto.txt | find / i / c“ D01”'）中执行SET cantLineasDetalle = %% i