when running batch file from java , 1 randomly appears before >>

Question

i am trying to run a batch file from my java code

this is the batch file line :

C:\\Users\\abdelk\\workspace\\Symmetrix>symconfigure -sid 13 -cmd \"c         


        

Answer 1

First, take a look on Microsoft's TechNet article using command redirection operators.

Numeric 1 is an equivalent for handle stdout (standard output).

In batch files numeric 1 is omitted on redirection stdout.

For example put those 2 lines into a batch file and run it

echo This is just a redirect test.>CapturedStandardOutput.txt
@pause

You will see that cmd.exe automatically inserts  1 (space and 1) left to the redirection operator >.

In general it is not advisable to add already in batch file 1 for stdout.

Why?

Look what is executed with:

echo This is just a redirect test.1>CapturedStandardOutput.txt
@pause

You see in console window:

echo This is just a redirect test.1 1>CapturedStandardOutput.txt

And the file CapturedStandardOutput.txt contains the line:

This is just a redirect test.1

The solution is to use in batch file:

echo This is just a redirect test. 1>CapturedStandardOutput.txt

This results in execution of the line:

echo This is just a redirect test.  1>CapturedStandardOutput.txt

And there is now the line below in file CapturedStandardOutput.txt:

This is just a redirect test. 

What you can't see here in the browser window is that the line in the text file ends now with a trailing space in comparison to first example. Therefore best is to use > and >> always without 1 as otherwise it is not really simple to control what is written to the text file.

One more hint:

To redirect a text to a file which ends with 1, 2, ..., 9 it is necessary to escape the number with ^.

Execution of a batch file with

echo Number is ^1>CapturedStandardOutput.txt
@pause

results in executing the command line

echo Number is 1 1>CapturedStandardOutput.txt

and in file CapturedStandardOutput.txt the line

Number is 1

with no trailing space at end of the line.

0 left to > and >> must not be escaped to get number 0 written into a text file.