Immediately print a string on stdout without new line?

Ruby
1

Hi everyone!

I’m trying to do something like this:

print "Processing… "

#some fancy code that takes ages, or maybe:
sleep(3)

print “done\n”

I was expecting to get the following output on my console:

Processing… [and after 3 secs:]done

However, the script first waits 3 seconds and then writes the whole line
at once. If I change the first line to

print “Processing…\n”

everything works as expected. But that’s not really what I want. Is
there another way of doing this?

Thanks, Janus

2

On Jul 15, 2008, at 5:09 PM, Janus B. wrote:

I was expecting to get the following output on my console:

Processing… [and after 3 secs:]done

However, the script first waits 3 seconds and then writes the whole
line
at once.

Try this:

print "Processing… "
STDOUT.flush

sleep 3

puts “done”

STDOUT#flush will ensure that everything in the buffer will be
printed, there and then

~ Ari
English is like a pseudo-random number generator - there are a
bajillion rules to it, but nobody cares.

3

On Tue, Jul 15, 2008 at 3:09 PM, Janus B. [email protected]
wrote:

everything works as expected. But that’s not really what I want. Is
there another way of doing this?

Thanks, Janus

Posted via http://www.ruby-forum.com/.

Janus this works for me:

def processing
print "Processing… "
sleep(3)
print “done!”
end

processing

–
“Hey brother Christian with your high and mighty errand, Your actions
speak
so loud, I can’t hear a word you’re saying.”

-Greg Graffin (Bad Religion)

4

fedzor wrote:

Try this:

print "Processing… "
STDOUT.flush

sleep 3

puts “done”

STDOUT#flush will ensure that everything in the buffer will be
printed, there and then

Thank you! That does the trick…

Glen H. wrote:

Janus this works for me:

def processing
print "Processing… "
sleep(3)
print “done!”
end

processing

Strange, on my machine (Ruby 1.86 on Linux) "Processing… " and “done!”
appear at the same time (after the 3 seconds).

5

On Jul 15, 2008, at 3:17 PM, fedzor wrote:

STDOUT#flush will ensure that everything in the buffer will be
printed, there and then

Another option …

STDOUT.sync = true
print "Processing… "

The sync flag will cause the IO stream to be flushed after every
write / print / puts.

Blessings,
TwP

6

Another option: print your message to stderr, not stdout. Stderr is
usually not buffered by the OS (for exactly this sort of reason).

Dave

7

On Tue, Jul 15, 2008 at 3:26 PM, Janus B. [email protected]
wrote:

STDOUT#flush will ensure that everything in the buffer will be
print "Processing… "
Posted via http://www.ruby-forum.com/.

Until reading fedzor’s post I had completely forgotten that different
Operating systems behave differently. I’m on a Windows machine here at
work. Glad you got it fixed though.

–
“Hey brother Christian with your high and mighty errand, Your actions
speak
so loud, I can’t hear a word you’re saying.”

-Greg Graffin (Bad Religion)