(quickie) print in place?

[Damian]

was wondering how exactly do you print(...) in place? Like the percent
counter for installers like linux's rpm. In other words so the output
keeps going to the same spot in stead of advancing the cursor.

If this is something only on Linux/Unix thats fine, as thats the only
place I really need to do this. Though portability never hurts.

Many thanks.

 

[gnari]

was wondering how exactly do you print(...) in place? Like the percent
counter for installers like linux's rpm. In other words so the output
keeps going to the same spot in stead of advancing the cursor.

If this is something only on Linux/Unix thats fine, as thats the only
place I really need to do this. Though portability never hurts.

"\r"

gnari

 

[Ben Morrow]

was wondering how exactly do you print(...) in place? Like the percent
counter for installers like linux's rpm. In other words so the output
keeps going to the same spot in stead of advancing the cursor.

If this is something only on Linux/Unix thats fine, as thats the only
place I really need to do this. Though portability never hurts.

Term::ANSIScreen.

Ben

 

[Damian]

"\r"

gnari

This this a good way of doing it? This is what I just tried:

#!/usr/local/bin/perl -w

use strict;

$| = 1; # Needs to be non zero so you cna see print's in a loop.

for my $i (0..10) {
my $c = $i * 10;
print "Percent complete: $c %\r";

sleep(1); # Sleep for 1 second.
}
print "Percent complete: Done!\n"


I notice though that that if you hit a key while it's looping (logged
into ssh), it shifts the whole thing over, then the next itereation
comes along and rewites that portion, ending up with the right hand bit
of text from the shifted part rtemaining there. Is the only way to make
sure that everything up to the end of thel ine is cleared, short of
manually padding it with spaces, which would require I find out the
column width and then find out how much space is left. Theres gotta be a
beter way to do this.

 

[Damian]

gnari wrote:
I notice though that that if you hit a key while it's looping (logged
into ssh), it shifts the whole thing over, then the next itereation
comes along and rewites that portion, ending up with the right hand
bit of text from the shifted part rtemaining there. Is the only way
to make sure that everything up to the end of thel ine is cleared,
short of manually padding it with spaces, which would require I find
out the column width and then find out how much space is left. Theres
gotta be a beter way to do this.

Or would it be bettter to supress input / local echo? Is this even
possible and a good way to go about this?

 

[Ben Morrow]

Or would it be bettter to supress input / local echo? Is this even
possible and a good way to go about this?

Depending on what you're doing, yes, it may well be.

See Term::ReadKey and (as I said before) Term::ANSIScreen.

Ben

 

[James Willmore]

On Mon, 09 Feb 2004 18:30:05 -0800, Damian wrote:

This this a good way of doing it? This is what I just tried:

#!/usr/local/bin/perl -w

use strict;

$| = 1; # Needs to be non zero so you cna see print's in a loop.

for my $i (0..10) {
my $c = $i * 10;
print "Percent complete: $c %\r";

sleep(1); # Sleep for 1 second.
}
print "Percent complete: Done!\n"


I notice though that that if you hit a key while it's looping (logged
into ssh), it shifts the whole thing over, then the next itereation
comes along and rewites that portion, ending up with the right hand bit
of text from the shifted part rtemaining there. Is the only way to make
sure that everything up to the end of thel ine is cleared, short of
manually padding it with spaces, which would require I find out the
column width and then find out how much space is left. Theres gotta be a
beter way to do this.

If you want to have a progress bar or something similar, try
Term:rogressBar.

HTH

--
Jim

Copyright notice: all code written by the author in this post is
released under the GPL. http://www.gnu.org/licenses/gpl.txt
for more information.

a fortune quote ...
This fortune is inoperative. Please try another.

 

[Brad Baxter]

was wondering how exactly do you print(...) in place? Like the percent
counter for installers like linux's rpm. In other words so the output
keeps going to the same spot in stead of advancing the cursor.

If this is something only on Linux/Unix thats fine, as thats the only
place I really need to do this. Though portability never hurts.

You've gotten answers that are surely more correct and more portable, but
I typically use this technique for "quickie" progress reporting:

perl -e '$|++;for(1..10){printf "%6d%s", $_, "\b"x6; sleep 1}'

Yes, it suffers from the same problems you mentioned re \r.

Regards,

Brad