diff --git a/src/confirm.c b/src/confirm.c
new file mode 100644
index 0000000..2bfe73d
--- /dev/null
+++ b/src/confirm.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2021 Dylan Lom <djl@dylanlom.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <strings.h>
+
+#include "util.h"
+
+const char *argv0;
+
+/*
+ * Display msg, and prompt user for choice from opts.
+ * Returns index of chosen opt.
+ *
+ * First option (opts[0]) is default if nothing else matches
+ * Comparison is case insensitive
+ */
+int
+confirm(const char *msg, const char **opts, int opts_count)
+{
+    if (opts_count < 2) return 0;
+
+    char *opt0 = str_dupe(opts[0], sizeof(opts[0]));
+    printf("%s [%s", msg, str_toupper(opt0, strlen(opt0)));
+    free(opt0);
+    for (int i = 1; i < opts_count; i++) {
+        printf("/%s", opts[i]);
+    }
+    printf("]: ");
+
+    char *resp = NULL;
+    size_t n = 0;
+    getline(&resp, &n, stdin);
+    str_trimr(resp, '\n', 1);
+
+    for (int i = 0; i < opts_count; i++) {
+        if (strncasecmp(opts[i], resp, n) == 0) return i;
+    }
+
+    return 0;
+}
+
+/*
+ * Get user confirmation
+ * Examples:
+ *   $ confirm
+ *   $ confirm "Exit?"
+ *   $ confirm "Download file?" n y
+ *   $ confirm "What color?" red yellow blue
+ */
+int
+main(int argc, const char *argv[])
+{
+    SET_ARGV0();
+
+    // Options provided as args
+    if (argc > 1) return confirm(argv[0], argv+1, argc-1);
+
+    const char **opts = STR_EALLOC(2);
+    opts[0] = "y";
+    opts[1] = "n";
+    return confirm(argc == 1 ? argv[0] : "Are you sure?", opts, 2);
+}
diff --git a/src/confirm.sh b/src/confirm.sh
deleted file mode 100755
index f2f9eec..0000000
--- a/src/confirm.sh
+++ /dev/null
@@ -1,26 +0,0 @@
-#!/usr/bin/env sh
-#
-# confirm: get user confirmation
-# author: Dylan Lom <djl@dylanlom.com>
-#
-# Copyright (C) 2021 Dylan Lom <djl@dylanlom.com>
-#
-# Permission to use, copy, modify, and/or distribute this software for any purpose
-# with or without fee is hereby granted.
-#
-# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
-# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
-# FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
-# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
-# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
-# TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-# THIS SOFTWARE.
-#
-
-truthy "$1" \
-    && msg="$1" \
-    || msg="Are you sure you want to do that?"
-printf "%s [Y/n]: " "$msg"
-read resp
-test ! "$resp" = 'N' -a ! "$resp" = 'n'
-
diff --git a/src/util.c b/src/util.c
index 05c3262..41dfa0d 100644
--- a/src/util.c
+++ b/src/util.c
@@ -13,6 +13,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdarg.h>
@@ -51,6 +52,14 @@ ecalloc(size_t nmemb, size_t size)
     return ptr;
 }
 
+char *
+str_dupe(const char *s, size_t n)
+{
+    char *r = STR_EALLOC(n);
+    strncpy(r, s, n);
+    return r;
+}
+
 size_t
 str_pushc(char *s, char c, size_t s_size, size_t realloc_amount)
 {
@@ -105,3 +114,12 @@ str_concat(int count, ...)
 
     return new_str;
 }
+
+char *
+str_toupper(char *s, size_t n)
+{
+    for (size_t i = 0; i < n; i++) {
+        if islower(s[i]) s[i] = toupper(s[i]);
+    }
+    return s;
+}
diff --git a/src/util.h b/src/util.h
index ff61bc7..6189c44 100644
--- a/src/util.h
+++ b/src/util.h
@@ -9,8 +9,10 @@ void     edie(const char *fmt, ...);
 
 void    *ecalloc(size_t nmemb, size_t size);
 
+char    *str_dupe(const char *s, size_t n);
 size_t   str_pushc(char *s, char c, size_t size, size_t realloc_amount);
 int      str_trimr(char *s, char c, int max_num);
 char    *str_concat(int count, ...);
+char    *str_toupper(char *s, size_t n);
 #define  STR_EALLOC(s) ecalloc((s), sizeof(char))
 #define  STR_MALLOC(s) calloc((s), sizeof(char))