Add -z option to uniq. Originally proposed by Egmont Koblinger.

* NEWS: Mention uniq's new option: --zero-terminated (-z).
* src/uniq.c: Add new option, --zero-terminated (-z), to make
uniq use the NUL byte as separator/delimiter rather than newline.
(check_file): Add a parameter: delimiter.  Update caller.
Use readlinebuffer_delim in place of readlinebuffer everywhere.
(main): Handle the new option.
(usage): Describe new option the same way sort does.
* doc/coreutils.texi (uniq invocation): Describe the new option.

1 files changed, 18 insertions, 1 deletions

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 6fc72ec2f..cc4d0b853 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -4229,11 +4229,15 @@ This is equivalent to @option{--all-repeated} (@option{-D}).
 
 @item prepend
 Output a newline before each group of repeated lines.
+With @option{--zero-terminated} (@option{-z}), use
+an @acronym{ASCII} @sc{nul} (zero) byte instead of a newline.
 
 @item separate
 Separate groups of repeated lines with a single newline.
+With @option{--zero-terminated} (@option{-z}), use
+an @acronym{ASCII} @sc{nul} (zero) byte instead of a newline.
 This is the same as using @samp{prepend}, except that
-there is no newline before the first group, and hence
+no delimiter is inserted before the first group, and hence
 may be better suited for output direct to users.
 @end table
 
@@ -4261,6 +4265,19 @@ Compare at most @var{n} characters on each line (after skipping any specified
 fields and characters).  By default the entire rest of the lines are
 compared.
 
+@item -z
+@itemx --zero-terminated
+@opindex -z
+@opindex --zero-terminated
+@cindex sort zero-terminated lines
+Treat the input as a set of lines, each terminated by a null character
+(@acronym{ASCII} @sc{nul}) instead of a line feed
+(@acronym{ASCII} @sc{lf}).
+This option can be useful in conjunction with @samp{sort -z}, @samp{perl -0} or
+@samp{find -print0} and @samp{xargs -0} which do the same in order to
+reliably handle arbitrary file names (even those containing blanks
+or other special characters).
+
 @end table
 
 @exitstatus