add sort

Makefile

@@ -5,8 +5,8 @@ LIB = util/afgets.o util/agetcwd.o util/concat.o util/enmasse.o util/eprintf.o \
       util/recurse.o
 
 SRC = basename.c cat.c chmod.c chown.c date.c dirname.c echo.c false.c grep.c \
-      head.c ln.c ls.c mkdir.c mkfifo.c nl.c pwd.c rm.c sleep.c tail.c tee.c \
-      touch.c true.c wc.c
+      head.c ln.c ls.c mkdir.c mkfifo.c nl.c pwd.c rm.c sleep.c sort.c tail.c \
+      tee.c touch.c true.c wc.c
 OBJ = $(SRC:.c=.o) $(LIB)
 BIN = $(SRC:.c=)
 MAN = $(SRC:.c=.1)

sort.1

@@ -0,0 +1,15 @@
+.TH NL 1 sbase\-VERSION
+.SH NAME
+sort \- sort lines
+.SH SYNOPSIS
+.B sort
+.RB [ \-r ]
+.RI [ file ...]
+.SH DESCRIPTION
+.B sort
+writes the sorted concatenation of the given files to stdout.  If no file is
+given, sort reads from stdin.
+.SH OPTIONS
+.TP
+.BI \-r
+reverses the sort.

sort.c

@@ -0,0 +1,71 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "text.h"
+#include "util.h"
+
+static int linecmp(const char **, const char **);
+static void getlines(FILE *, const char *);
+
+static bool rflag = false;
+static char **lines = NULL;
+static long nlines = 0;
+
+int
+main(int argc, char *argv[])
+{
+	char c;
+	long i;
+	FILE *fp;
+
+	while((c = getopt(argc, argv, "r")) != -1)
+		switch(c) {
+		case 'r':
+			rflag = true;
+			break;
+		default:
+			exit(EXIT_FAILURE);
+		}
+	if(optind == argc)
+		getlines(stdin, "<stdin>");
+	else for(; optind < argc; optind++) {
+		if(!(fp = fopen(argv[optind], "r")))
+			eprintf("fopen %s:", argv[optind]);
+		getlines(fp, argv[optind]);
+		fclose(fp);
+	}
+	qsort(lines, nlines, sizeof *lines, (int (*)(const void *, const void *))linecmp);
+
+	for(i = 0; i < nlines; i++) {
+		fputs(lines[i], stdout);
+		free(lines[i]);
+	}
+	free(lines);
+
+	return EXIT_SUCCESS;
+}
+
+void
+getlines(FILE *fp, const char *str)
+{
+	char *line = NULL;
+	size_t size = 0;
+
+	while(afgets(&line, &size, fp)) {
+		if(!(lines = realloc(lines, ++nlines * sizeof *lines)))
+			eprintf("realloc:");
+		if(!(lines[nlines-1] = malloc(strlen(line)+1)))
+			eprintf("malloc:");
+		strcpy(lines[nlines-1], line);
+	}
+	free(line);
+}
+
+int
+linecmp(const char **a, const char **b)
+{
+	return strcmp(*a, *b) * (rflag ? -1 : +1);
+}