1 files changed, 75 insertions, 0 deletions
diff --git a/src/commands/tee.c b/src/commands/tee.c
new file mode 100644
index 0000000..224463c
--- /dev/null
+++ b/src/commands/tee.c
@@ -0,0 +1,75 @@
+#include "../command.h"
+
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+
+
+static void help() {
+    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");
+    exit(EXIT_SUCCESS);
+}
+
+static void handle(){}
+
+static void run_tee(int file_count, FILE* files[file_count]) {
+    char c;
+    while((c = getchar()) != EOF) {
+        for (int i = 0; i < file_count; i++) {
+            fwrite(&c, 1, 1, files[i]);
+            fflush(files[i]);
+        }
+        putchar(c);
+    }
+    for (int i = 0; i < file_count; i++) {
+        fclose(files[i]);
+    }
+}
+
+COMMAND(tee) {
+
+    bool append = false;
+    bool handle_sigint = false;
+
+    int start = 0;
+    for (int i = 0; i < argc; i++) {
+        if (!prefix("-", argv[i])) break;
+        if (streql("--help", argv[i])) help();
+
+        start++;
+        for (size_t j = 1; j < strlen(argv[i]); j++) {
+            char o = argv[i][j];
+            switch (o) {
+                case 'a':
+                    append = true;
+                    break;
+                case 'i':
+                    handle_sigint = true;
+                    break;
+                default:
+                    error("error: unkown option: %c", o);
+            }
+        }
+    }
+
+    if (handle_sigint) {
+        signal(SIGINT, handle);
+    }
+
+    if (argc - start < 1) {
+        run_tee(0, NULL);
+        return EXIT_SUCCESS;
+    }
+
+    FILE* files[argc - start];
+    for (int i = start; i < argc; i++) {
+        FILE* file = get_file(argv[i], append ? "a" : "w");
+        files[i - start] = file;
+    }
+
+    run_tee(argc - start, files);
+    return EXIT_SUCCESS;
+}