yuriy_zubarev wrote:
> I'm curious if there is a command line tool that would
> transform the file by padding each line with spaces so that it's
> exactly 50 characters long.

I'm surprised that nobody has thought to give the solution
in the one command utility that has always been provided
to do exactly this.

>From memory; not tested:

dd if=my/file bs=50 conv=block,noerror,sync

=Brian

On 2006-08-17, bsh wrote:
>
> yuriy_zubarev wrote:
>> I'm curious if there is a command line tool that would
>> transform the file by padding each line with spaces so that it's
>> exactly 50 characters long.
>
> I'm surprised that nobody has thought to give the solution
> in the one command utility that has always been provided
> to do exactly this.
>
>>From memory; not tested:
>
> dd if=my/file bs=50 conv=block,noerror,sync

That's probably because it doesn't do what the OP asked for.

--
Chris F.A. Johnson, author <http://cfaj.freeshell.org>
Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
===== My code in this post, if any, assumes the POSIX locale
===== and is released under the GNU General Public Licence

Chris F.A. Johnson wrote:
> On 2006-08-17, bsh wrote:
> > yuriy_zubarev wrote:
> padding each line with spaces so that it's exactly 50 characters long.
> > I'm surprised ... dd(1)
> probably because it doesn't do what the OP asked for.

I'm at the relative disadvantage of not being currently able to test
my submission, but as I (re)read the OQ, this should do exactly
what the OP asked for.

So what do you think it does?

=Brian

On 2006-08-17, bsh wrote:
>
> Chris F.A. Johnson wrote:
>> On 2006-08-17, bsh wrote:
>> > yuriy_zubarev wrote:
>> padding each line with spaces so that it's exactly 50 characters long.
>> > I'm surprised ... dd(1)
>> probably because it doesn't do what the OP asked for.
>
> I'm at the relative disadvantage of not being currently able to test
> my submission, but as I (re)read the OQ, this should do exactly
> what the OP asked for.
>
> So what do you think it does?

$ printf "%s\n" a b c d e f g > txt
$ dd if=txt bs=50 conv=block,noerror,sync | od -c
0+1 records in
1+0 records out
0000000 a \n b \n c \n d \n e \n f \n g \n \0 \0
0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
*
0000060 \0 \0
0000062

--
Chris F.A. Johnson, author <http://cfaj.freeshell.org>
Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
===== My code in this post, if any, assumes the POSIX locale
===== and is released under the GNU General Public Licence

Chris F.A. Johnson wrote:
> bsh wrote:
> > Chris F.A. Johnson wrote:
> > > bsh wrote:
> > > > yuriy_zubarev wrote:

> $ dd if=txt bs=50 conv=block,noerror,sync | od -c
> 0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0

Hmmm... What I read in the dd(1) manpage before posting was:

sync
Pad every input block with NULs to ibs-size; when
used with block or unblock, pad with spaces rather than NULs.

Maybe a variant or GNU extension? Once upon a time, using
dd(1) extensively with SVR3/4, I distinctly remember dd(1)
performing the expected behavior.

=Brian

On 2006-08-17, bsh wrote:
>
> Chris F.A. Johnson wrote:
>> bsh wrote:
>> > Chris F.A. Johnson wrote:
>> > > bsh wrote:
>> > > > yuriy_zubarev wrote:
>
>> $ dd if=txt bs=50 conv=block,noerror,sync | od -c
>> 0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
>
> Hmmm... What I read in the dd(1) manpage before posting was:
>
> sync
> Pad every input block with NULs to ibs-size; when
> used with block or unblock, pad with spaces rather than NULs.

It also removes the newlines:

$ dd if=~/txt cbs=50 bs=50 conv=block | hd
0+1 records in
7+0 records out
0: 61 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 a
16: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
32: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
48: 20 20 62 20 20 20 20 20 20 20 20 20 20 20 20 20 b
64: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
80: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
96: 20 20 20 20 63 20 20 20 20 20 20 20 20 20 20 20 c
112: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
128: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
144: 20 20 20 20 20 20 64 20 20 20 20 20 20 20 20 20 d
160: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
176: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
192: 20 20 20 20 20 20 20 20 65 20 20 20 20 20 20 20 e
208: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
224: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
240: 20 20 20 20 20 20 20 20 20 20 66 20 20 20 20 20 f
256: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
272: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
288: 20 20 20 20 20 20 20 20 20 20 20 20 67 20 20 20 g
304: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
320: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20
336: 20 20 20 20 20 20 20 20 20 20 20 20 20 20


> Maybe a variant or GNU extension?

Possibly.

> Once upon a time, using dd(1) extensively with SVR3/4, I distinctly
> remember dd(1) performing the expected behavior.

And there was no block conversion in SVR3.2 (for which I have a
manual).

--
Chris F.A. Johnson, author <http://cfaj.freeshell.org>
Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
===== My code in this post, if any, assumes the POSIX locale
===== and is released under the GNU General Public Licence