GNU bug report logs - #77179
seq incorrectly(?) pads output when last parameter magnitude larger than last printed number

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Nicolas Boichat <nicolas <at> boichat.ch>
To: bug-coreutils <at> gnu.org
Subject: seq incorrectly(?) pads output when last parameter magnitude larger
 than last printed number
Date: Sat, 22 Mar 2025 13:36:13 +0100

[Message part 1 (text/plain, inline)]

Hi,

Version: seq (GNU coreutils) 9.6; OS: Archlinux, x86-64

When adding `-w` parameter, we want numbers to be padded with leading 0s,
e.g. this looks correct:
$ seq -w 0 5 10
00
05
10

However, the behaviour is perhaps incorrect when the last printed number
magnitude is lower than the last parameter, e.g:
$ seq -w 0 6 10
00
06
would probably be more correct with this output:
0
6

The manual makes no promise about this ("Print all numbers with the same
width, by padding with leading zeros"), but it's still a bit odd to add a
superfluous 0.

Also, it is especially confusing because, on the other hand, the precision
of the last parameter is ignored, as if it was just a bound that played no
role in formatting:
$ seq 0 5 10.00001
0
5
10

While
$ seq 0.0000 5 10
0.0000
5.0000
10.0000

Side note, a solution would also need to make sure that this still works:
$ seq -w 0 5 12
00
05
10

Thanks,

[Message part 2 (text/html, inline)]

Message #8 received at 77179 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Nicolas Boichat <nicolas <at> boichat.ch>, 77179 <at> debbugs.gnu.org
Subject: Re: bug#77179: seq incorrectly(?) pads output when last parameter
 magnitude larger than last printed number
Date: Sat, 22 Mar 2025 19:18:40 +0000

On 22/03/2025 12:36, Nicolas Boichat wrote:
> Hi,
> 
> Version: seq (GNU coreutils) 9.6; OS: Archlinux, x86-64
> 
> When adding `-w` parameter, we want numbers to be padded with leading 0s,
> e.g. this looks correct:
> $ seq -w 0 5 10
> 00
> 05
> 10
> 
> However, the behaviour is perhaps incorrect when the last printed number
> magnitude is lower than the last parameter, e.g:
> $ seq -w 0 6 10
> 00
> 06
> would probably be more correct with this output:
> 0
> 6
> 
> The manual makes no promise about this ("Print all numbers with the same
> width, by padding with leading zeros"), but it's still a bit odd to add a
> superfluous 0.
> 
> Also, it is especially confusing because, on the other hand, the precision
> of the last parameter is ignored, as if it was just a bound that played no
> role in formatting:
> $ seq 0 5 10.00001
> 0
> 5
> 10
> 
> While
> $ seq 0.0000 5 10
> 0.0000
> 5.0000
> 10.0000
> 
> Side note, a solution would also need to make sure that this still works:
> $ seq -w 0 5 12
> 00
> 05
> 10

Yes we could do better here,though there are many edge cases as you've noted.
I suspect though that -w currently suffices for the
vast majority of cases it's needed for.

thanks,
Pádraig

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