How to make a cycling counter from commandline?


#1

Hi, I’m looking for a way to implement this idea:


count=1
total=15

until count>total
print “Record #{count} of #{total} processed.”
count+=1
end

I want this to print out in a Linux shell. However, I’d prefer it if
there was a way to have this counter increment without printing a new
line. As in, from the user’s perspective the ‘count’ would just
increment until it matched the total… all taking place on the same
line.

I know I’ve seen this done, but can Ruby do this?


#2

On 11/7/06, removed_email_address@domain.invalid removed_email_address@domain.invalid wrote:

end

I want this to print out in a Linux shell. However, I’d prefer it if
there was a way to have this counter increment without printing a new
line. As in, from the user’s perspective the ‘count’ would just
increment until it matched the total… all taking place on the same
line.

I know I’ve seen this done, but can Ruby do this?

Search the archives for count or counter. It was discussed last week or
so.


#3

On 11/7/06, removed_email_address@domain.invalid removed_email_address@domain.invalid wrote:

end

$ cat tmp.rb

STDOUT.sync = true

total = ARGV[0] || 15
count = 1

until count>total
print “\rRecord #{count} of #{total} processed”
count += 1
sleep 0.25
end

print “\n”

That should do you what you want. The secret is the carriage return
“\r” at the beginning of the print string. That will bring the cursor
back to the beginning of the line and then overwrite anything
currently on that line.

Blessings,
TwP


#4

On 11/7/06, Tim P. removed_email_address@domain.invalid wrote:

count+=1
end

$ cat tmp.rb

STDOUT.sync = true

total = ARGV[0] || 15

total = ARGV[0] || 15
total = Integer(total) # need to turn any passed in arguments into an
integer


#5

Tim P. wrote:

print “Record #{count} of #{total} processed.”
total = ARGV[0] || 15

That should do you what you want. The secret is the carriage return
“\r” at the beginning of the print string. That will bring the cursor
back to the beginning of the line and then overwrite anything
currently on that line.

From my BBS years I remember adding… mmm… ¿"\033[K"? at the end of
the string when I did this kind of overwriting. That ANSI code (if I
remembered it correctly) clears everything until the end of line
–useful in case the new string is shorter than the overwritten one.
(This doesn’t happen in this case, but maybe the OP wants to print
“#{total} record processed” afterwards.)

Greetings.


#6

On 11/7/06, Carlos removed_email_address@domain.invalid wrote:

From my BBS years I remember adding… mmm… ¿"\033[K"? at the end of
the string when I did this kind of overwriting. That ANSI code (if I
remembered it correctly) clears everything until the end of line
–useful in case the new string is shorter than the overwritten one.
(This doesn’t happen in this case, but maybe the OP wants to print
“#{total} record processed” afterwards.)

Yeah, that was the fatal flaw in my little post there. That is one
very cool ANSI code though. I’ve used the color codes, but did not
know about that one :slight_smile:

I just tried it out, and that is the correct code :slight_smile:

clear = “\e[K”
print “a very long line of text that is longer than the next line”
sleep 1
print “\rshort line of text#{clear}”
sleep 1
print “\n”

By the way “\e” == “\033”

Blessings,
TwP


#7

Tim P. wrote:

That should do you what you want. The secret is the carriage return
“\r” at the beginning of the print string. That will bring the cursor
back to the beginning of the line and then overwrite anything
currently on that line.

Smells unportable between Linux, Windows, and Mac Classic. Then again, I
don’t know what approach Ruby takes to newline-handling on non-Unix
platforms.

Ah, the good old days of high-school Turbo Pascal, when gotoxy() Just
Worked ™. Nary a control character or escape sequence in sight.

David V.


#8

On Wed, 8 Nov 2006, Tim P. wrote:

sleep 0.25
Blessings,
TwP

man, you learn something every day! that’s pretty sweet.

-a


#9

On 11/7/06, David V. removed_email_address@domain.invalid wrote:

“\r” is completely portable. win32 platforms use a “\r\n” for the end
of a line, and *NIX uses just a single “\n” – hence the dos2unix
utility.

Now, the ANSI control character to clear to the end of a line
(mentioned earlier in this thread) is definitely not portable to the
win32 cmd shell.

TwP


#10

Il giorno 08/nov/06, alle ore 00:15, David V. ha scritto:

Smells unportable between Linux, Windows, and Mac Classic. Then
again, I
don’t know what approach Ruby takes to newline-handling on non-Unix
platforms.

A portable way (but maybe overkill for this) is by using the ncurses
library.
I never tried ncurses-ruby, though.

Ah, the good old days of high-school Turbo Pascal, when gotoxy() Just
Worked ™. Nary a control character or escape sequence in sight.

ncurses also has gotoxy :slight_smile:


#11

David V. [mailto:removed_email_address@domain.invalid]

Tim P. wrote:

> That should do you what you want. The secret is the carriage return

> “\r” at the beginning of the print string. That will bring

the cursor

> back to the beginning of the line and then overwrite anything

> currently on that line.

Smells unportable between Linux, Windows, and Mac Classic.

Then again, I

don’t know what approach Ruby takes to newline-handling on non-Unix

platforms.

fyi, code posted by TwP runs on linux and windows.

kind regards -botp


#12

Tim P. [mailto:removed_email_address@domain.invalid]

I just tried it out, and that is the correct code :slight_smile:

clear = “\e[K”

print “a very long line of text that is longer than the next line”

sleep 1

print “\rshort line of text#{clear}”

sleep 1

print “\n”

i just do something like

MAX=foo_integer||80
CR="\r"
s=foo_string[0…MAX].ljust(MAX) #or rjust or center

print CR+s

kind regards -botp