From dc940832736fe47d91b70fe993bbe0d8245c857f Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Mon, 21 Sep 2020 17:06:36 +0000
Subject: [PATCH] xargs: add some long options for GNU compatibility

These are low-effort to add, so let's just do it.

Reported by:	"LukeShu" on Hacker News (-r / --no-run-if-empty)
MFC after:	1 week
---
 usr.bin/xargs/xargs.1 | 18 +++++++++---------
 usr.bin/xargs/xargs.c | 19 ++++++++++++++++++-
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/usr.bin/xargs/xargs.1 b/usr.bin/xargs/xargs.1
index a0b6624d967d..f5f9bbfaa7cd 100644
--- a/usr.bin/xargs/xargs.1
+++ b/usr.bin/xargs/xargs.1
@@ -33,7 +33,7 @@
 .\" $FreeBSD$
 .\" $xMach: xargs.1,v 1.2 2002/02/23 05:23:37 tim Exp $
 .\"
-.Dd June 11, 2020
+.Dd September 21, 2020
 .Dt XARGS 1
 .Os
 .Sh NAME
@@ -84,7 +84,7 @@ Any single character, including newlines, may be escaped by a backslash.
 .Pp
 The options are as follows:
 .Bl -tag -width indent
-.It Fl 0
+.It Fl 0 , Fl -null
 Change
 .Nm
 to expect NUL
@@ -175,7 +175,7 @@ If EOF is reached and fewer lines have been read than
 then
 .Ar utility
 will be called with the available lines.
-.It Fl n Ar number
+.It Fl n Ar number , Fl -max-args= Ns Ar number
 Set the maximum number of arguments taken from standard input for each
 invocation of
 .Ar utility .
@@ -201,7 +201,7 @@ in the child process before executing the command.
 This is useful if you want
 .Nm
 to run an interactive application.
-.It Fl P Ar maxprocs
+.It Fl P Ar maxprocs , Fl -max-procs= Ns Ar maxprocs
 Parallel mode: run at most
 .Ar maxprocs
 invocations of
@@ -212,7 +212,7 @@ If
 is set to 0,
 .Nm
 will run as many processes as possible.
-.It Fl p
+.It Fl p , Fl -interactive
 Echo each command to be executed and ask the user whether it should be
 executed.
 An affirmative response,
@@ -221,7 +221,7 @@ in the POSIX locale,
 causes the command to be executed, any other response causes it to be
 skipped.
 No commands are executed if the process is not attached to a terminal.
-.It Fl r
+.It Fl r , Fl -no-run-if-empty
 Compatibility with GNU
 .Nm .
 The GNU version of
@@ -263,7 +263,7 @@ can use for replacements.
 The default for
 .Ar replsize
 is 255.
-.It Fl s Ar size
+.It Fl s Ar size , Fl -max-chars= Ns Ar size
 Set the maximum number of bytes for the command line length provided to
 .Ar utility .
 The sum of the length of the utility name, the arguments passed to
@@ -277,10 +277,10 @@ The current default value for
 is
 .Dv ARG_MAX
 - 4096.
-.It Fl t
+.It Fl t , Fl -verbose
 Echo the command to be executed to standard error immediately before it
 is executed.
-.It Fl x
+.It Fl x , Fl -exit
 Force
 .Nm
 to terminate immediately if a command line containing
diff --git a/usr.bin/xargs/xargs.c b/usr.bin/xargs/xargs.c
index 6ee3f36e2495..e69314e58fa3 100644
--- a/usr.bin/xargs/xargs.c
+++ b/usr.bin/xargs/xargs.c
@@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <getopt.h>
 #include <langinfo.h>
 #include <locale.h>
 #include <paths.h>
@@ -98,6 +99,22 @@ static volatile int childerr;
 
 extern char **environ;
 
+static const char *optstr = "+0E:I:J:L:n:oP:pR:S:s:rtx";
+
+static const struct option long_options[] =
+{
+	{"exit",		no_argument,		NULL,	'x'},
+	{"interactive",		no_argument,		NULL,	'p'},
+	{"max-args",		required_argument,	NULL,	'n'},
+	{"max-chars",		required_argument,	NULL,	's'},
+	{"max-procs",		required_argument,	NULL,	'P'},
+	{"no-run-if-empty",	no_argument,		NULL,	'r'},
+	{"null",		no_argument,		NULL,	'0'},
+	{"verbose",		no_argument,		NULL,	't'},
+
+	{NULL,			no_argument,		NULL,	0},
+};
+
 int
 main(int argc, char *argv[])
 {
@@ -137,7 +154,7 @@ main(int argc, char *argv[])
 		nline -= strlen(*ep++) + 1 + sizeof(*ep);
 	}
 	maxprocs = 1;
-	while ((ch = getopt(argc, argv, "0E:I:J:L:n:oP:pR:S:s:rtx")) != -1)
+	while ((ch = getopt_long(argc, argv, optstr, long_options, NULL)) != -1)
 		switch (ch) {
 		case 'E':
 			eofstr = optarg;