Catching a system call output

ruby-talk
1

Hi,
I've a Ruby prog with a system call to latex like this one :
system('latex -interaction=nonstopmode temp.tex')
It works fine, but I wanted to catch the output inside an array (or
variable), but not in my terminal.
How can I do that ? Thanks for your response :
6TooL9

2

You can use backticks to capture stdout:

text = `latex -interaction=nonstopmode temp.tex`

Regards,

Sean

···

On 11/7/05, Tool69 <kibleur.christophe@gmail.com> wrote:

Hi,
I've a Ruby prog with a system call to latex like this one :
system('latex -interaction=nonstopmode temp.tex')
It works fine, but I wanted to catch the output inside an array (or
variable), but not in my terminal.
How can I do that ? Thanks for your response :
6TooL9

3

Try

output = `latex -interaction=nonstopmode temp.tex`

(note that the symbols above are backticks, not quotation marks)

or dive into popen.

cheers,

Brian

···

On 07/11/05, Tool69 <kibleur.christophe@gmail.com> wrote:

Hi,
I've a Ruby prog with a system call to latex like this one :
system('latex -interaction=nonstopmode temp.tex')
It works fine, but I wanted to catch the output inside an array (or
variable), but not in my terminal.
How can I do that ? Thanks for your response :
6TooL9

--
http://ruby.brian-schroeder.de/

Stringed instrument chords: http://chordlist.brian-schroeder.de/

4

Hi,
I've a Ruby prog with a system call to latex like this one :
system('latex -interaction=nonstopmode temp.tex')
It works fine, but I wanted to catch the output inside an array (or
variable), but not in my terminal.
How can I do that ? Thanks for your response :

  open('|latex -interaction=nonstopmode temp.tex') do |stream|
    #then maybe...
    stream.readlines.each do |line
    end
  end

See also IO.popen, and others [cf Ruby-Talk:163897]

6TooL9

        Hugh

···

On Tue, 8 Nov 2005, Tool69 wrote:

5

Thank you very much for your answers, I'll try them. I've just received
my book on ruby "Programming Ruby, 2nd Ed" , I think that it will be
very useful!
6TooL9

6

So it works perfectly, but I got one more question :
what can I do if I have a variable inside my system call, like :
system("latex -interaction=nonstopmode #{@myvar}")
I tried with backticks, but it doesn't seems to work :
`latex -interaction=nonstopmode #{@myvar}`
Any solution ? Thanks again !

7

Works for me:
$ ruby -e 'test = 42; p `echo "#{test}"`'
"42\n"

···

On 07/11/05, Tool69 <kibleur.christophe@gmail.com> wrote:

So it works perfectly, but I got one more question :
what can I do if I have a variable inside my system call, like :
system("latex -interaction=nonstopmode #{@myvar}")
I tried with backticks, but it doesn't seems to work :
`latex -interaction=nonstopmode #{@myvar}`
Any solution ? Thanks again !

--
http://ruby.brian-schroeder.de/

Stringed instrument chords: http://chordlist.brian-schroeder.de/

8

Thanks Brian, I forgot the "" inside !