Output redirection in windows


#1

I am using the one-click installer on windows (RC2). I can not get
output redirection to work with Kernel.system. Consider the following
code

F:\tmp\cont-test\test>cat test.rb
def test(command)
puts command
puts Kernel.system(command)
puts “---------------------------”
end

test(“mpto mp-test-01.mp”)
test(“mpto mp-test-01.mp > mp-test-01-test.tex”)

mpto.exe is a helper program that comes with metapost and is part of
most tex
distributions. It is included in my path environment. I have a file
mp-test-01.mp in the current directory. mpto scans the .mp file and
outputs on
stdout. I want to redirect that output to a file. But > does not work.

Running this program gives

F:\tmp\cont-test\test>ruby test.rb
mpto mp-test-01.mp
\gdef\mpxshipout{\shipout\hbox\bgroup
\setbox0=\hbox\bgroup}
\gdef\stopmpxshipout{\egroup \dimen0=\ht0 \advance\dimen0\dp0
\dimen1=\ht0 \dimen2=\dp0
\setbox0=\hbox\bgroup
\box0
\ifnum\dimen0>0 \vrule width1sp height\dimen1 depth\dimen2
\else \vrule width1sp height1sp depth0sp\relax
\fi\egroup
\ht0=0pt \dp0=0pt \box0 \egroup}
\mpxshipout% line 2 mp-test-01.mp
This is a test\stopmpxshipout
\end{document}
true

mpto mp-test-01.mp > mp-test-01-test.tex
false

system “mpto …” executes correctly (the true after \end{document})
while system “mpto … > …” fails. No mp-test-01-test.tex file is
created.

When I give the same commands from cmd.exe they work. I am confused why
something as simple as output redirection is not working. What is the
correct
way to do this?

Thanks,
Aditya


#2

It works for me on the latest One-Click:

C:_Ryan\downloads>irb
irb(main):001:0> system(‘echo “hello world!” > hello.txt’)
=> true
irb(main):002:0> exit

C:_Ryan\downloads>type hello.txt
“hello world!”

Another option is to do the redirection yourself:

File.open(‘output.txt’, ‘w’) do |file|
IO.popen(‘dir’) do |pipe|
pipe.each do |line|
file.print line
end
end
end

Ryan


#3

On Sun, 7 May 2006, Ryan L. wrote:

It works for me on the latest One-Click:

C:_Ryan\downloads>irb
irb(main):001:0> system(‘echo “hello world!” > hello.txt’)
=> true
irb(main):002:0> exit

C:_Ryan\downloads>type hello.txt
“hello world!”

Strange, I get

E:\Temp>irb
irb(main):001:0> system(‘echo “hello world” > hello.txt’)
=> false
irb(main):002:0> exit

E:\Temp>type hello.txt
The system cannot find the file specified.

Can it be because I also have cygwin installed?

Another option is to do the redirection yourself:

File.open(‘output.txt’, ‘w’) do |file|
IO.popen(‘dir’) do |pipe|
pipe.each do |line|
file.print line
end
end
end

How can I pass arguments to the pipe?
E:\Temp>irb
irb(main):003:0> File.open(‘output.txt’, ‘w’) do |file|
irb(main):004:1* IO.popen(‘echo “Hello world”’) do |pipe|
irb(main):005:2* pipe.each do |line|
irb(main):006:3* file.print line
irb(main):007:3> end
irb(main):008:2> end
irb(main):009:1> end
Errno::ENOENT: No such file or directory - echo “Hello world”
from (irb):4:in `popen’
from (irb):4
from (irb):3

Ryan

Thanks,
Aditya


#4

On 5/7/06, Aditya M. removed_email_address@domain.invalid wrote:

Strange, I get

E:\Temp>irb
irb(main):001:0> system(‘echo “hello world” > hello.txt’)
=> false

This false result means that system could not find echo.

Can it be because I also have cygwin installed?

It may be related. The problem is that the system method cannot
execute what you are trying to run. It might be related to your path
or who knows what.

Errno::ENOENT: No such file or directory - echo “Hello world”

Again this seems to be a problem with your environment.

Ryan