2 files changed, 88 insertions, 3 deletions

diff --git a/command/sync.c b/command/sync.c
new file mode 100644
index 0000000..797d7a5
--- /dev/null
+++ b/command/sync.c
@@ -0,0 +1,85 @@
+#include "args.h"
+#include "command.h"
+#include "lslib.h"
+
+#define _X_OPEN_SOURCE 500
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+static struct {
+    bool sync_fs;
+    bool sync_data;
+} flags;
+
+static void help (void) {
+    printf("Usage: sync [-df] [FILE]...\n\n");
+    printf("Write all buffered blocks (in FILEs) to disk\n\n");
+	printf("\t-d\tAvoid syncing metadata\n");
+#ifdef _GNU_SOURCE
+	printf("\t-f\tSync filesystems underlying FILEs\n");
+#endif
+}
+
+static int short_arg (char c, char* next) {
+    UNUSED(next);
+    switch (c) {
+        case 'd':
+            flags.sync_data = true;
+            break;
+#ifdef _GNU_SOURCE
+        case 'f':
+            flags.sync_fs = true;
+            break;
+#endif
+        default:
+            return ARG_INVALID;
+    }
+    return ARG_UNUSED;
+}
+
+static bool sync_file(char* path) {
+    int fd;
+    int ret;
+
+    fd = open(path, O_NOCTTY | O_RDONLY | O_NONBLOCK);
+    if (fd < 0) {
+        return false;
+    }
+
+    if (flags.sync_fs) {
+#ifdef _GNU_SOURCE
+        ret = syncfs(fd) >= 0;
+#else 
+        ret = 0;
+#endif
+    } else {
+        ret = flags.sync_data ? fdatasync(fd) : fsync(fd);
+        if (ret < 0) {
+            error_s("failed to sync '%s': %s", path, strerror(errno));
+        }
+    }
+
+    close(fd);
+    return ret;
+}
+
+COMMAND(sync_cmd) {
+
+    int start, i, ret = EXIT_SUCCESS;
+    
+    start = parse_args(argc, argv, help, short_arg, NULL);
+
+    if (argc - start < 1) {
+        sync();
+        return EXIT_SUCCESS;
+    }
+
+    for (i = start; i < argc; i++) {
+        if (!sync_file(argv[i])) ret = EXIT_FAILURE;
+    }
+
+    return ret;
+}
diff --git a/command/tee.c b/command/tee.c
index 0462517..364a13d 100644
--- a/command/tee.c
+++ b/command/tee.c
@@ -12,8 +12,8 @@ static struct {
 static void help(void) {
     printf("Usage: tee [-ai] [FILE]...\n\n");
     printf("Copy stdin to each FILE, and also to stdout\n\n");
-	printf("\t-a	Append to the given FILEs, don't overwrite\n");
-	printf("\t-i	Ignore interrupt signals (SIGINT)\n");
+	printf("\t-a\tAppend to the given FILEs, don't overwrite\n");
+	printf("\t-i\tIgnore interrupt signals (SIGINT)\n");
     exit(EXIT_SUCCESS);
 }
 
@@ -52,7 +52,7 @@ static int short_arg(char c, char* next) {
     return ARG_UNUSED;
 }
 
-COMMAND(tee) {
+COMMAND(tee_cmd) {
 
     int start, i;
     FILE** files;