diff --git a/examples/README.md b/examples/README.md
index 0ebf81e..9bb5e70 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -6,6 +6,7 @@ Each of these examples demonstrates one aspect or feature of argc.
 - [multiline.sh](./multiline.sh) - how to use multiline help text.
 - [nested-commands](./nested-commands.sh) - how to use nested commands.
 - [hooks.sh](./hooks.sh) - how to use argc hooks.
+- [strict.sh](./strict.sh) - how to use strict mode
 - [parallel.sh](./parallel.sh) - how to use `--argc-parallel`.
 
 - [args.sh](./args.sh) - all kinds of `@arg`.
diff --git a/examples/strict.sh b/examples/strict.sh
new file mode 100755
index 0000000..aa0d05d
--- /dev/null
+++ b/examples/strict.sh
@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+set -eu
+
+
+# @flag      --fa 
+# @option    --oa                   
+# @option    --of*,                 multi-occurs + comma-separated list
+# @option    --oda=a                default
+# @option    --oca[a|b]             choice
+# @option    --ofa[`_choice_fn`]    choice from fn
+# @option    --oxa~                 capture all remaining args
+
+main() {
+    ( set -o posix ; set ) | grep ^argc_
+    echo "${argc__fn:-}" "$@"
+}
+
+_choice_fn() {
+    echo abc
+    echo def
+	echo ghi
+}
+
+eval "$(argc --argc-eval "$0" "$@")"
\ No newline at end of file
diff --git a/src/build.rs b/src/build.rs
index 600a2ea..05b11d2 100644
--- a/src/build.rs
+++ b/src/build.rs
@@ -13,7 +13,7 @@ const UTIL_FNS: [(&str, &str); 6] = [
 _argc_take_args() {
     _argc_take_args_values=()
     _argc_take_args_len=0
-    local param="${1:-}" min="${2:-}" max="${3:-}" signs="${4:-}" delimiter="${5:-}"
+    local param="$1" min="$2" max="$3" signs="$4" delimiter="$5"
     if [[ "$min" -eq 0 ]] && [[ "$max" -eq 0 ]]; then
         return
     fi
@@ -140,7 +140,7 @@ _argc_require_params() {
         r#"
 _argc_validate_choices() {
     local render_name="$1" raw_choices="$2" choices item choice concated_choices=""
-    IFS=$'\n' read -d '' -r -a choices <<<"$raw_choices"
+    IFS=$'\n' read -r -a choices <<<"$raw_choices"
     for choice in "${choices[@]}"; do
         if [[ -z "$concated_choices" ]]; then
             concated_choices="$choice"
diff --git a/tests/cli.rs b/tests/cli.rs
index a219a80..ea6bf3f 100644
--- a/tests/cli.rs
+++ b/tests/cli.rs
@@ -98,10 +98,10 @@ fn build_stdout() {
 }
 
 #[test]
-fn build_outpath() {
-    let path = locate_script("examples/demo.sh");
+fn run_build() {
+    let path = locate_script("examples/strict.sh");
     let tmpdir = tmpdir();
-    let outpath = tmpdir.join("demo.sh");
+    let outpath = tmpdir.join("strict.sh");
     Command::cargo_bin("argc")
         .unwrap()
         .arg("--argc-build")
@@ -109,8 +109,23 @@ fn build_outpath() {
         .arg(&outpath)
         .assert()
         .success();
-    let script = std::fs::read_to_string(&outpath).unwrap();
-    assert!(script.contains("# ARGC-BUILD"));
+
+    Command::cargo_bin("argc")
+        .unwrap()
+        .arg("--argc-run")
+        .arg(&outpath)
+        .args([
+            "--fa",
+            "--oa",
+            "oa1",
+            "--of=of1,of2",
+            "--oca=a",
+            "--ofa",
+            "abc",
+        ])
+        .assert()
+        .stdout(predicates::str::contains("argc__fn=main"))
+        .success();
 }
 
 #[test]
diff --git a/tests/fixtures.rs b/tests/fixtures.rs
index 77a5f1f..129e825 100644
--- a/tests/fixtures.rs
+++ b/tests/fixtures.rs
@@ -116,7 +116,6 @@ pub fn run_script<T: AsRef<Path>>(
     let envs: HashMap<&str, &str> = envs.iter().cloned().collect();
     let shell_path = argc::NativeRuntime.shell_path().unwrap();
     let output = std::process::Command::new(shell_path)
-        .arg("-u")
         .arg(script_path.as_ref())
         .args(args)
         .env("PATH", path_env_var.clone())
diff --git a/tests/validate.rs b/tests/validate.rs
index 53eaefb..1206c43 100644
--- a/tests/validate.rs
+++ b/tests/validate.rs
@@ -249,7 +249,7 @@ fn choice_access_vars() {
 # @flag --fa
 # @arg val[`_choice_fn`]
 _choice_fn() {
-	if [[ ${argc_fa:-} == 1 ]]; then
+	if [[ $argc_fa == 1 ]]; then
 		echo abc
 	else
 		echo def
@@ -266,10 +266,10 @@ fn choice_slash() {
 # @arg foo
 # @arg bar[`_choice_fn`]
 cmd() {
-    echo ${1:-}
+    echo $1
 }
 _choice_fn() {
-    echo ${1:-}
+    echo $1
 }
 "###;
     snapshot_multi!(script, [vec!["prog", "cmd", "a\\b", "a\\b"],]);