1#!/bin/sh
2# When reading a specified number of lines, ensure that the output
3# file pointer is positioned just after those lines.
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_ head
22
23(echo a; echo b) > in || framework_failure_
24echo b > exp || framework_failure_
25
26for i in -1 1; do
27  (head -n $i >/dev/null; cat) < in > out || fail=1
28  compare exp out || fail=1
29done
30
31# Exercise the (start_pos < pos) block in elide_tail_lines_seekable.
32# So far, this is the only test to do that.
33# Do that by creating a file larger than BUFSIZ (I've seen 128K) and
34# elide a suffix of it (by line count) that is also larger than BUFSIZ.
35# 50000 lines times 6 bytes per line gives us enough leeway even on a
36# system with a BUFSIZ of 256K.
37n_lines=50000
38seq 70000 > in2 || framework_failure_
39echo $n_lines > exp-n || framework_failure_
40
41(head -n-$n_lines>/dev/null; wc -l) < in2 > n
42compare exp-n n || fail=1
43
44Exit $fail
45