Simple "table" command for pipe testing

Makefile

@@ -30,6 +30,7 @@ STAGE_BIN=$(STAGE)/init \
 		  $(STAGE)/sbin/insmod \
 		  $(STAGE)/sbin/reboot \
 		  $(STAGE)/sbin/lspci \
+		  $(STAGE)/bin/table \
 		  $(STAGE)/bin/vsh \
 		  $(STAGE)/bin/grep \
 		  $(STAGE)/test.ko

core/bin/table.c

@@ -0,0 +1,61 @@
+#include <sys/ioctl.h>
+#include <termios.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+    // 25 x 3
+    size_t width;
+    size_t cols = 4;
+    struct winsize winsz;
+    int index = 0;
+    char linebuf[1024];
+
+    if (!isatty(STDOUT_FILENO)) {
+        fprintf(stderr, "stdout is not a TTY\n");
+        return -1;
+    }
+
+    // Get terminal width
+    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &winsz) != 0) {
+        perror("stdout");
+        return -1;
+    }
+
+    width = (winsz.ws_col - 1) / cols;
+
+    while (fgets(linebuf, sizeof(linebuf), stdin)) {
+        // Remove trailing \n
+        char *p = strchr(linebuf, '\n');
+        if (p && *linebuf) {
+            *p = 0;
+        }
+
+        // Skip leading whitespace
+        p = linebuf;
+        while (isspace(*p)) {
+            ++p;
+        }
+
+        size_t len = strlen(p);
+        if (len > width) {
+            len = width;
+        }
+
+        fwrite(p, 1, len, stdout);
+        for (size_t i = len; i < width; ++i) {
+            fputc(' ', stdout);
+        }
+        if ((++index) == cols) {
+            fputc('\n', stdout);
+            index = 0;
+        }
+    }
+    if (index != 0) {
+        fputc('\n', stdout);
+    }
+    fflush(stdout);
+    return 0;
+}