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