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