Help with batch file- read Nth line in delimited text file

[RForte]

I used the search and couldn't find any topics that answered my question.  If topics like this already exist, I apologize.

I have to write a batch file in DOS for work that requires me to take information from a specified line in a comma-delimited file, and be able to change the 2nd field which serves as a flagging system.

For instance, if I run the batch file, it prompts me for a number - I want to be able to enter 2079, have it go to the 2079th line, return whatever is in the first field as an argument or variable, and change the second field from 0 to 1 (the flagging system).

If it were linux, I'd have no problem, but I don't know how to do this with DOS/Windows batch files.  I'd greatly appreciate any assistance in writing this batch file.

[gh0std0g74]

vbscript

Code: [Select]

Set objFS=CreateObject("Scripting.FileSystemObject")
strFile = "c:\test\file"
Set objFile = objFS.OpenTextFile(strFile)
Do Until objFile.AtEndOfLine
linenumber = objFile.Line
strLine = objFile.ReadLine
If linenumber = 2049 Then
WScript.Echo linenumber
csv = Split(strLine,",")
csv(1) = "new value" 'change 2nd field
strLine = Join(csv,",")
End If
WScript.Echo strLine
Loop
objFile.Close
usage

Code: [Select]

c:\test> cscript /nologo myscript.vbs

since you know linux, and if you can download stuff, there is more simpler way to do that, using gawk (see my sig ) for windows

Code: [Select]

C:\test>gawk -F"," "NR==2049{$2=\"new\"}1" OFS="," file


[Salmon Trout]

For instance, if I run the batch file, it prompts me for a number - I want to be able to enter 2079, have it go to the 2079th line, return whatever is in the first field as an argument or variable, and change the second field from 0 to 1 (the flagging system).

Do you then need to write out the complete file to disk, replacing the previous version?

[billrich]

REM  Don't ask for line number; use command line argument :
test10.bat 2079
rem if flag is set to 0, will not change to 1
Change this line of code:
if !c! EQU %1  set str2=!str:,1,=,0,! && echo.!str2! >> newdata.txt
to
if !c! EQU %1  set str2=!str:,0,=,1,! && echo.!str2! >> newdata.txt
(* see Below)

Code: [Select]

@ echo off

setLocal EnableDelayedExpansion

echo.  > newdata.txt
set /a c=0
for /f "delims==" %%a in (testdata.txt) do (

set /a c+=1
if !c! NEQ %1 echo %%a  >> newdata.txt


if !c! EQU %1 set str=%%a && echo.!str!
rem if !c! EQU %1  set str2=!str:,1,=,0,! && echo.!str2! >> newdata.txt
if !c! EQU %1  set str2=!str:,0,=,1,! && echo.!str2! >> newdata.txt



)
echo.
echo newdata.txt
echo.

type newdata.txt

echo.
echo old testdata.txt
echo.
type  testdata.txt

Output:

C:\> test10.bat  5
5,1,mess,nothing

newdata.txt


1,0,mess,nothing
2,0,mess,nothing
3,0,mess,nothing
4,0,mess,nothing
5,0,mess,nothing

old testdata.txt

1,0,mess,nothing
2,0,mess,nothing
3,0,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

C:\>

Reference:
http://www.dostips.com/DtTipsStringManipulation.php#Snippets.Replace

____________________________________
*Below:

C:\>test10.bat 3
3,0,mess,nothing

newdata.txt


1,0,mess,nothing
2,0,mess,nothing
3,1,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

old testdata.txt

1,0,mess,nothing
2,0,mess,nothing
3,0,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

C:\>

[billrich]

C:\>type field1.bat

Code: [Select]

@echo off
REM  use command line argument for line number  field1.bat 3

setLocal EnableDelayedExpansion

set /a c=0
for /f "tokens=1,2* delims==," %%i in (testdata.txt) do (

set /a c+=1

set Field1=%%i

if !c! EQU %1 echo  Field one is !Field1!


)C:\>field1.bat 3
 Field one is 3

C:\>
C:\>field1.bat 5
 Field one is 5

C:\>
C:\>type  testdata.txt
1,0,mess,nothing
2,0,mess,nothing
3,0,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

C:\>

[Geek-9pm]

How was this comma delimited file created?
If it was the output of a spreadsheet, you might use the macro language of the original program to get what you need.

[billrich]

gh0std0g74,

I ran your myscript.vbs with my test data:


C:\test>type  myscript.vbs

Code: [Select]

Set objFS=CreateObject("Scripting.FileSystemObject")
strFile = "c:\testdata.txt"
Set objFile = objFS.OpenTextFile(strFile)
Do Until objFile.AtEndOfLine
        linenumber = objFile.Line
        strLine = objFile.ReadLine
        If linenumber = 3 Then
                WScript.Echo linenumber
                csv = Split(strLine,",")
                csv(1) = "new value" 'change 2nd field
                strLine = Join(csv,",")
        End If
        WScript.Echo strLine
Loop
objFile.CloseC:\test>cscript /nologo myscript.vbs
1,0,mess,nothing
2,0,mess,nothing
3
3,new value,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

C:\test>

The output for the second field ( flag field ) should be a "0" or "1";
your program put "new value."
Also, the number 3 record remains?
Is testdata.txt not good test data?


C:\>type testdata.txt
1,0,mess,nothing
2,0,mess,nothing
3,0,mess,nothing
4,0,mess,nothing
5,1,mess,nothing

C:\>

[gh0std0g74]

@billrich, what are you suggesting? that i do everything nicely for OP?

[billrich]

@billrich, what are you suggesting? that i do everything nicely for OP?

Yes and for me.  I have never  run *.vbs script.  I'm trying to learn something new at 72.

The line number (2049) is hardcoded  in the script.  Would not a variable or command argument work better?

You have had questions about my code in the past.  I learn from such questions.  I'm still a newbie with batch.  My code for this problem works but has several bugs. The first field save could/should be part of second field replace?

[gh0std0g74]

Yes and for me.  I have never  run *.vbs script.  I'm trying to learn something new at 72.

the questions you posed has very very trivial solutions to it, that's why i was puzzled about it. I mean, its not as if there's a logic problem in my code that you don't understand.

The line number (2049) is hardcoded  in the script.  Would not a variable or command argument work better?

of course , putting it into a variable or argument is better... and that's also trivial to do. setting variables and using command line arguments are so common in programming languages that the only thing you need to ever do is look up the syntax for it. With vbscript, see here for example.

The first field save could/should be part of second field replace?

i am going to assume i know what you are asking... do you mean csv(1) ?? its the 2nd field. When you split a string in vbscript using split() , the first array element that is returned has index 0, which is the first field.


please look at my sig (link for vbscript manual) if you are interested.

[billrich]

the questions you posed has very very trivial solutions to it, that's why i

You should move to *.vbs area and leave the batch area for batch script.

[gh0std0g74]

You should move to *.vbs area and leave the batch area for batch script.

no, the moderator should do that, not me. Besides, no where in this forum is there any rules that say vbs is not allowed.  I am going to pose this question to you again.... what EXACTLY is a batch script/file? if you an accurately tell me the answer, i will give it to you.

[billrich]

no, the moderator should do that, not me. Besides, no where in this forum is there any rules that say vbs is not allowed.  I am going to pose this question to you again.... what EXACTLY is a batch script/file? if you an accurately tell me the answer, i will give it to you.

Definition of: BAT file

(BATch file) A file of DOS commands, which are executed one after the other. It has a .BAT extension and is created with a text editor . See DOS batch file and DOS AUTOEXEC.BAT.


http://www.pcmag.com/encyclopedia_term/0,2542,t=BAT+file&i=38451,00.asp

A file that contains a sequence, or batch, of commands. Batch files are useful for storing sets of commands that are always executed together because you can simply enter the name of the batch file instead of entering each command individually.
In DOS systems, batch files end with a.BAT extension. For example, the following DOS batch file prints the date and time and sets the prompt to GO>:
date
time
prompt [GO>]
http://www.webopedia.com/TERM/B/batch_file.html

[billrich]

no, the moderator should do that, not me. Besides, no where in this forum is there any rules that say vbs is not allowed.  I am going to pose this question to you again.... what EXACTLY is a batch script/file? if you an accurately tell me the answer, i will give it to you.

GhostDog,

I'm pulling your leg.  We like to see your VBS and other code.

Keep posting.   But post your Output along with your code. 

[gh0std0g74]

Definition of: BAT file

(BATch file) A file of DOS commands, which are executed one after the other. It has a .BAT extension and is created with a text editor . See DOS batch file and DOS AUTOEXEC.BAT.


http://www.pcmag.com/encyclopedia_term/0,2542,t=BAT+file&i=38451,00.asp

A file that contains a sequence, or batch, of commands. Batch files are useful for storing sets of commands that are always executed together because you can simply enter the name of the batch file instead of entering each command individually.
In DOS systems, batch files end with a.BAT extension. For example, the following DOS batch file prints the date and time and sets the prompt to GO>:
date
time
prompt [GO>]
http://www.webopedia.com/TERM/B/batch_file.html

there you go....

A file that contains a sequence, or batch, of commands. .... Batch files are useful for storing sets of commands .. .....

a quiz for you....tell me if the code below is a batch file....

Code: [Select]

@echo off
setLocal EnableDelayedExpansion
cscript /nologo myscript.vbs > newfile
mv newfile original file
for /F %%a in ('type file') do (echo %%a)

the above, contains a series of commands as defined by your definition....