From 9a2bef433271cd830d318e5b17efc38ac74e34a3 Mon Sep 17 00:00:00 2001
From: Christian Neukirchen <chneukirchen@gmail.com>
Date: Mon, 2 Nov 2015 22:32:48 +0100
Subject: -R to fail when no arguments are passed

---
 README.md |  6 +++++-
 xe.c      | 11 ++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 1940209..631d590 100644
--- a/README.md
+++ b/README.md
@@ -21,12 +21,13 @@ Over apply:
 
 ## Usage:
 
-	xe [-0knv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...
+	xe [-0Rknv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...
 	   | -s SHELLSCRIPT
 	   | -a COMMAND... -- ARGS...
 	   | -A ARGSEP COMMAND... ARGSEP ARGS...
 
 * `-0`: input filenames are seperated by NUL bytes (default: newlines).
+* `-R`: return with status 122 when no arguments have been passed.
 * `-k`: keep going: don't stop when a command failed to execute.
 * `-n`: don't run the commands, just print them.
 * `-v`: print commands before running them.
@@ -55,6 +56,9 @@ Like GNU and OpenBSD xargs:
 * 127 if the command is not found
 * 1 if some other error occurred.
 
+Additionally, 122 is returned when `-R` is passed and no
+input/arguments were passed.
+
 ## Installation
 
 Use `make all` to build, `make install` to install relative to `PREFIX`
diff --git a/xe.c b/xe.c
index 2578b6d..f9c7206 100644
--- a/xe.c
+++ b/xe.c
@@ -29,7 +29,8 @@ static char *sflag;
 static int maxatonce = 1;
 static int maxjobs = 1;
 static int runjobs = 0;
-static int aflag, kflag, nflag, vflag;
+static int Rflag, aflag, kflag, nflag, vflag;
+static int iterations = 0;
 
 static char *
 xstrdup(const char *s)
@@ -143,6 +144,7 @@ run(char *cmd[])
 	if (runjobs >= maxjobs)
 		mywait();
 	runjobs++;
+	iterations++;
 
 	if (vflag || nflag)
 		trace(cmd);
@@ -181,12 +183,13 @@ main(int argc, char *argv[])
 	int i, cmdend;
 	char *arg, **cmd;
 
-	while ((c = getopt(argc, argv, "+0A:I:N:aj:kns:v")) != -1)
+	while ((c = getopt(argc, argv, "+0A:I:N:Raj:kns:v")) != -1)
 		switch(c) {
 		case '0': delim = '\0'; break;
 		case 'A': argsep = optarg; aflag++; break;
 		case 'I': replace = optarg; break;
 		case 'N': maxatonce = atoi(optarg); break;
+		case 'R': Rflag++; break;
 		case 'a': aflag++; break;
 		case 'j': maxjobs = atoi(optarg); break;
 		case 'k': kflag++; break;
@@ -195,7 +198,7 @@ main(int argc, char *argv[])
 		case 'v': vflag++; break;
 		default:
 			fprintf(stderr, 
-			    "Usage: %s [-0knv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...\n"
+			    "Usage: %s [-0Rknv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...\n"
 			    "     | -s SHELLSCRIPT\n"
 			    "     | -a COMMAND... -- ARGS...\n"
 			    "     | -A ARGSEP COMMAND... ARGSEP ARGS...\n",
@@ -263,5 +266,7 @@ main(int argc, char *argv[])
 
 	free(cmd);
 	free(getarg_line);
+	if (Rflag && iterations == 0)
+		return 122;
 	return 0;
 }
-- 
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