head,tail: add the -z,--zero-terminated option

* doc/coreutils.texi: Reference the option description.
* src/head.c: Parameterize the delimiter character.
* src/tail.c: Likewise.
* tests/misc/head.pl: Add test case.
* tests/misc/tail.pl: Likewise.
* NEWS: Mention the new feature.

2 files changed, 8 insertions, 0 deletions

diff --git a/tests/misc/head.pl b/tests/misc/head.pl
index 78644f2a5..1f565cf16 100755
--- a/tests/misc/head.pl
+++ b/tests/misc/head.pl
@@ -72,6 +72,10 @@ my @Tests =
   ['no-oct-2', '-010', {IN=>"\n"x12}, {OUT=>"\n"x10}],
   ['no-oct-3', '-n 08', {IN=>"\n"x12}, {OUT=>"\n"x8}],
   ['no-oct-4', '-c 08', {IN=>"\n"x12}, {OUT=>"\n"x8}],
+
+  # --zero-terminated
+  ['zero-1', '-z -n 1',  {IN=>"x\0y"}, {OUT=>"x\0"}],
+  ['zero-2', '-z -n 2',  {IN=>"x\0y"}, {OUT=>"x\0y"}],
 );
 
 @Tests = triple_test \@Tests;
diff --git a/tests/misc/tail.pl b/tests/misc/tail.pl
index c23102fe8..0d9bc4834 100755
--- a/tests/misc/tail.pl
+++ b/tests/misc/tail.pl
@@ -101,6 +101,10 @@ my @tv = (
 
 # With textutils-1.22, this failed.
 ['f-pipe-1', '-f -n 1', "a\nb\n", "b\n", 0],
+
+# --zero-terminated
+['zero-1', '-z -n 1', "x\0y", "y", 0],
+['zero-2', '-z -n 2', "x\0y", "x\0y", 0],
 );
 
 my @Tests;