[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: How can redirection operator aka ">" open output in append instead o
From: |
gentoo_eshoes |
Subject: |
Re: How can redirection operator aka ">" open output in append instead of ordinary write mode? |
Date: |
Fri, 17 Apr 2020 22:10:31 +0200 (CEST) |
the only issue I've encountered with this so far is that 'dd' will fail some of
its tests because it's not using of= but instead using the redir operator and
then it assumes it's NOT open in append mode ;)) so then it tries to seek past
EOF (which doesn't work in append mode) to make holes(of zeroes).
to illustrate:
$ rm /tmp/out;echo abcdefghijklm | dd bs=5 seek=8 oflag=seek_bytes > /tmp/out ;
stat --format=%s /tmp/out
2+1 records in
2+1 records out
14 bytes copied, 0.0001584 s, 88.4 kB/s
Actually written to disk: '14' bytes (100.00%).
14
the normal output should be(ie. file size 22 bytes not 14):
$ rm /tmp/out;echo abcdefghijklm | dd bs=5 seek=8 oflag=seek_bytes > /tmp/out ;
stat --format=%s /tmp/out
2+1 records in
2+1 records out
14 bytes copied, 0.000112444 s, 125 kB/s
Actually written to disk: '14' bytes (100.00%).
22
Not to worry though, I'm "sure" I pulled a Curly in Three Stooges episode
titled "A Plumbing We Will Go." when I added a kernel patch for this (attached)
which ensures `cannot seek: Illegal seek` when trying to go beyond EOF in
O_APPEND mode.
In a completely unrelated note, this cool Exolon theme/music, listening to it
right now: https://www.youtube.com/watch?v=Gfw-CIEM6Zs
ah memories:)
always_append_on_redirection.patch
Description: Text Data
deny_lseek_past_EOF_when_O_APPEND.patch
Description: Text Data
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: How can redirection operator aka ">" open output in append instead of ordinary write mode?,
gentoo_eshoes <=