From 4e9746c31473163b1abe868ec0e9bbef24d40cb1 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Sun, 30 Nov 2014 16:49:39 +0100
Subject: [PATCH] Add yes(1).

---
 doc/user-guide   |   1 +
 utils/.gitignore |   1 +
 utils/Makefile   |   1 +
 utils/yes.cpp    | 108 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 111 insertions(+)
 create mode 100644 utils/yes.cpp

diff --git a/doc/user-guide b/doc/user-guide
index 68092fd3..f9247f7b 100644
--- a/doc/user-guide
+++ b/doc/user-guide
@@ -195,6 +195,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
 * `uptime` - time since initialization
 * `wc` - count words and lines
 * `which` - find path to command
+* `yes` - repeatedly output a line
 
 Third Party Software
 --------------------
diff --git a/utils/.gitignore b/utils/.gitignore
index 42ece0d8..314a0aa9 100644
--- a/utils/.gitignore
+++ b/utils/.gitignore
@@ -47,3 +47,4 @@ uptime
 wc
 which
 xinstall
+yes
diff --git a/utils/Makefile b/utils/Makefile
index e8f9809d..4deec737 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -58,6 +58,7 @@ uniq \
 uptime \
 wc \
 which \
+yes \
 
 BINARIES=\
 $(BINARIES_EXCEPT_INSTALL) \
diff --git a/utils/yes.cpp b/utils/yes.cpp
new file mode 100644
index 00000000..4c554165
--- /dev/null
+++ b/utils/yes.cpp
@@ -0,0 +1,108 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This program is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by the Free
+    Software Foundation, either version 3 of the License, or (at your option)
+    any later version.
+
+    This program is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+    more details.
+
+    You should have received a copy of the GNU General Public License along with
+    this program. If not, see <http://www.gnu.org/licenses/>.
+
+    yes.cpp
+    Repeatedly output a line.
+
+*******************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "Usage: %s [STRING]...\n", argv0);
+	fprintf(fp, "  or:  %s OPTION\n", argv0);
+	fprintf(fp, "Repeatedly output a line with all specified STRING(s), or 'y'.\n");
+	fprintf(fp, "\n");
+	fprintf(fp, "      --help     display this help and exit\n");
+	fprintf(fp, "      --version  output version information and exit\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+	fprintf(fp, "License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.\n");
+	fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+	fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			while ( char c = *++arg ) switch ( c )
+			{
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				help(stderr, argv0);
+				exit(1);
+			}
+		}
+		else if ( !strcmp(arg, "--help") )
+			help(stdout, argv0), exit(0);
+		else if ( !strcmp(arg, "--version") )
+			version(stdout, argv0), exit(0);
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			help(stderr, argv0);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	while ( true )
+	{
+		if ( argc == 1 )
+		{
+			printf("y");
+		}
+		else
+		{
+			for ( int i = 1; i < argc; i++ )
+				printf("%s%s", 1 < i ? " " : "", argv[i]);
+		}
+		printf("\n");
+	}
+
+	return 0;
+}