pr: Add ps && hexdump (#26)

* Adding hexdump and ps.c

* Add hexdump and ps command descriptions to help

* Update with missing ;

src/userland/cli/hexdump.c

@@ -0,0 +1,111 @@
+// Copyright (c) 2023-2026 Chris (boreddevnl)
+// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
+// This header needs to maintain in any file it is present in, as per the GPL license terms.
+// BOREDOS_APP_DESC: Display file contents in hexadecimal.
+
+#include "syscall.h"
+#include "stdlib.h"
+#include "string.h"
+#include "stdio.h"
+
+#define BYTES_PER_LINE 16
+
+static int sc_strcmp(const char *a, const char *b) {
+    while (*a && *a == *b) {
+        a++;
+        b++;
+    }
+
+    return (unsigned char)*a - (unsigned char)*b;
+}
+
+static void print_usage(void) {
+    printf("Usage: hexdump <file>\n");
+    printf("\n");
+    printf("Display file contents in hexadecimal.\n");
+}
+
+static void print_hex_byte(unsigned char b) {
+    const char *hex = "0123456789ABCDEF";
+
+    putchar(hex[(b >> 4) & 0xF]);
+    putchar(hex[b & 0xF]);
+}
+
+static void print_hex32(unsigned int v) {
+    const char *hex = "0123456789ABCDEF";
+
+    for (int i = 7; i >= 0; i--) {
+        putchar(hex[(v >> (i * 4)) & 0xF]);
+    }
+}
+
+int main(int argc, char **argv) {
+    int fd;
+    int offset = 0;
+
+    unsigned char buf[BYTES_PER_LINE];
+
+    if (argc < 2) {
+        print_usage();
+        return 1;
+    }
+
+    if (sc_strcmp(argv[1], "-h") == 0 ||
+        sc_strcmp(argv[1], "--help") == 0) {
+        print_usage();
+        return 0;
+    }
+
+    fd = sys_open(argv[1], "r");
+
+    if (fd < 0) {
+        printf("hexdump: cannot open '%s'\n", argv[1]);
+        return 1;
+    }
+
+    while (1) {
+        int bytes = sys_read(fd, buf, BYTES_PER_LINE);
+
+        if (bytes <= 0)
+            break;
+
+        // Offset
+        print_hex32(offset);
+        printf("  ");
+
+        // Hex bytes
+        for (int i = 0; i < BYTES_PER_LINE; i++) {
+            if (i < bytes) {
+                print_hex_byte(buf[i]);
+            } else {
+                printf("  ");
+            }
+
+            printf(" ");
+
+            if (i == 7)
+                printf(" ");
+        }
+
+        printf(" |");
+
+        // ASCII preview
+        for (int i = 0; i < bytes; i++) {
+            unsigned char c = buf[i];
+
+            if (c >= 32 && c <= 126)
+                putchar(c);
+            else
+                putchar('.');
+        }
+
+        printf("|\n");
+
+        offset += bytes;
+    }
+
+    sys_close(fd);
+
+    return 0;
+}