GNU bug report logs - #34332
GNU sed v.4.5 – Attempt to delete rows from output of command 'parted' fails

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 34332 in the body.
You can then email your comments to 34332 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

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

From: Ricky Tigg <ricky.tigg <at> gmail.com>
To: bug-sed <at> gnu.org
Subject: GNU sed v.4.5 – Attempt to delete rows from output of command 'parted' fails
Date: Tue, 5 Feb 2019 15:14:04 +0100

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

sed (GNU sed) 4.5 – Attempt to delete rows from output of command parted
fails. Command executed:

# parted /dev/sdc | sed '1,3d'

For comparison:

# parted /dev/sdc
GNU Parted 3.2
Using /dev/sdc
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted)

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

Message #8 received at 34332 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
To: Ricky Tigg <ricky.tigg <at> gmail.com>, 34332 <at> debbugs.gnu.org
Subject: Re: bug#34332: GNU sed v.4.5 – Attempt to delete rows from output of command 'parted' fails
Date: Tue, 5 Feb 2019 15:58:41 -0700

tags 34332 notabug
close 34332
stop

hello,

On 2019-02-05 7:14 a.m., Ricky Tigg wrote:
> sed (GNU sed) 4.5 – Attempt to delete rows from output of command parted
> fails. Command executed:
> 
> # parted /dev/sdc | sed '1,3d'

I don't think it failed - it worked exactly as you requested - deleting
the first three lines.

But...

> For comparison:
> 
> # parted /dev/sdc
> GNU Parted 3.2
> Using /dev/sdc
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted)
> 

"parted" is an interactive program, and piping its output into another
program is very likely to result in weird behavior.

In this case, the 4th line "(parted)" does not end with a newline
(because parted is interactive), and "sed" waits until a newline
is printed to process the line.

If you press "enter" several times (or type parted commands)
you'll see these commands appear on the screen, even when piped
to sed.

As such, I'm closing this as not-a-bug, but discussion can
continue by replying to this thread.

regards,
 - assaf

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.