batch file programming

Question

I tried to copy one file to another from starting line upto a limit. ie., line 1 to 10(file1.txt)->file2.txt but while writing "!" is skipped. what can i do for to solve it. Any help will be thankful.

The loop for that function is given below.

%NF%-> new file.

%EF%-> existing file

%1% -> line number(passed from another part)

:_doit

findstr /N /R "." %EF%|findstr /B /C:"%1:">nul

if errorlevel 1 (    
    echo. >>%NF%        
) else (    
    for /f "tokens=1 delims=" %%a in ('findstr /N /R "." %EF%^|findstr /B /C:"%1:"') do (    
        if [%%a] EQU [] (    
            echo. >>%NF%    
        ) else (    
            echo %%a >>%NF%    
       )     
   )
)

Community · Accepted Answer · 2017-05-23 12:11:47Z

3

If you can download tools, you can use GNU win32 gawk

gawk.exe "NR>10{exit}1"  file1 > file2

And you can take a look at this thread here that is similar

edited May 23, 2017 at 12:11

CommunityBot

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answered Sep 28, 2010 at 9:51

ghostdog74

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2 Comments

ghostdog74 Over a year ago

yes, its just a command. So put that command inside your batch file.

nr.iras.sk Over a year ago

Do you know what the reason for disappearing "!" symbol in batch file while writing from one file to another?

jeb · Accepted Answer · 2011-01-28 07:10:14Z

3

The reason is the delayed expansion, if you disable it, also the ! work as expected. You can disable it only for the loop.

if errorlevel 1 (    
    echo. >>%NF%        
) else (
   setlocal DisableDelayedExpansion
    for /f "tokens=1 delims=" %%a in ('findstr /N /R "." %EF%^|findstr /B /C:"%1:"') do (    
        if [%%a] EQU [] (    
            echo. >>%NF%    
        ) else (    
            echo %%a >>%NF%    
       )     
   )
   endlocal
)

The parser for batch lines has multiple phases: The first phase is the %var% expansion, then comes the special character phase "^<>&|() and after the %%a phase, the delayed (exclamation phase).

That's the reason why the ! dissappear in your case. Because you got something like this from your file %%a=Hello! Then the exclamation phase try to expand the !, but this fails and it is removed.

If in your file is the line Hello^! you got in your "copy" Hello!

But in a batch file you need two carets to display one !

echo hello^^!

Because in phase2, the ^^! is inflated to ^!, and in the exclamation phase the last caret escapes the !

edited Jan 28, 2011 at 7:10

answered Sep 30, 2010 at 18:02

jeb

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4 Comments

nr.iras.sk Over a year ago

But i placed the DisableDelayedExpansion in next else block to work properly.Thanks.

nr.iras.sk Over a year ago

if errorlevel 1 ( echo. >>%NF% ) else ( for /f "tokens=1 delims=" %%a in ('findstr /N /R "." %EF%^|findstr /B /C:"%1:"') do ( if [%%a] EQU [] ( echo. >>%NF% ) else( setlocal DisableDelayedExpansion echo %%a >>%NF% endlocal ) ) )

Joey Over a year ago

Note that for /f will skip empty lines.

jeb Over a year ago

Yes, but there can't be empty lines, because findstr /N always prepend the line number

nr.iras.sk · Accepted Answer · 2011-01-28 07:35:15Z

2

if errorlevel 1 ( 
    echo. >>%NF% 
) else ( 
    for /f "tokens=1 delims=" %%a in ('findstr /N /R "." %EF%^|findstr /B /C:"%1:"') do ( 
       if [%%a] EQU [] ( 
          echo. >>%NF% 
       ) else( 
          setlocal DisableDelayedExpansion 
          echo %%a >>%NF%
          endlocal
       ) 
    )
)

edited Jan 28, 2011 at 7:35

answered Jan 28, 2011 at 5:19

nr.iras.sk

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1 Comment

jeb Over a year ago

There are two problems, "echo." is two times slower as "echo(" and it fails if a file named "echo" exist. The second problem is with long files your code doesn't work, because you didn't use endlocal and therefore you get an overflow.

Benoit · Accepted Answer · 2010-09-25 09:52:02Z

1

Maybe use gawk.exe from UnxUtils :

gawk "NR<10" < file1 > file2

answered Sep 25, 2010 at 9:52

Benoit

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1 Comment

ghostdog74 Over a year ago

Better GNU gawk : gnuwin32.sourceforge.net/packages/gawk.htm

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