1#!/bin/sh
2# Demonstrate a bug in 'tail -cN' when operating on files of size 4G and larger
3# Fixed in coreutils-4.5.2.
4
5# Copyright (C) 2002-2023 Free Software Foundation, Inc.
6
7# This program is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16
17# You should have received a copy of the GNU General Public License
18# along with this program.  If not, see <https://www.gnu.org/licenses/>.
19
20. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
21print_ver_ tail
22expensive_
23
24# Create a file of size exactly 4GB (2^32) with 8 bytes
25# at the beginning and another set of 8 bytes at the end.
26# The rest will be NUL bytes.  On most modern systems, the following
27# creates a file that takes up only a few KB.  Here, du -sh says 16K.
28echo abcdefgh | tr -d '\n' > big || framework_failure_
29echo 87654321 | tr -d '\n' > tmp || framework_failure_
30# Seek 4GB - 8
31dd bs=1 seek=4294967288 if=tmp of=big 2> err || dd_failed=1
32if test "$dd_failed" = 1; then
33  cat err 1>&2
34  skip_ \
35'cannot create a file large enough for this test,
36possibly because this system does not support large files;
37Consider rerunning this test on a different file system.'
38fi
39
40
41tail -c1 big > out || fail=1
42# Append a newline.
43echo >> out
44cat <<\EOF > exp
451
46EOF
47
48compare exp out || fail=1
49
50Exit $fail
51