feat: support input redirects

mod.test.ts

@@ -1102,7 +1102,7 @@ Deno.test("piping in command", async () => {
   }
 });
 
-Deno.test("redirects", async () => {
+Deno.test("output redirects", async () => {
   await withTempDir(async (tempDir) => {
     // absolute
     const tempFile = tempDir.join("temp_file.txt");
@@ -1158,6 +1158,14 @@ Deno.test("redirects", async () => {
   });
 });
 
+Deno.test("input redirects", async () => {
+  await withTempDir(async (tempDir) => {
+    tempDir.join("test.txt").writeTextSync("Hi!");
+    const text = await $`cat - < test.txt`.text();
+    assertEquals(text, "Hi!");
+  });
+});
+
 Deno.test("shebang support", async (t) => {
   await withTempDir(async (dir) => {
     const steps: Promise<boolean>[] = [];

src/command.ts

@@ -1199,32 +1199,32 @@ function getSignalAbortCode(signal: Deno.Signal) {
 }
 
 export function template(strings: TemplateStringsArray, exprs: any[]) {
-  let result = "";
-  for (let i = 0; i < Math.max(strings.length, exprs.length); i++) {
-    if (strings.length > i) {
-      result += strings[i];
-    }
-    if (exprs.length > i) {
-      result += templateLiteralExprToString(exprs[i], escapeArg);
-    }
-  }
-  return result;
+  return templateInner(strings, exprs, escapeArg);
 }
 
 export function templateRaw(strings: TemplateStringsArray, exprs: any[]) {
-  let result = "";
+  return templateInner(strings, exprs, undefined);
+}
+
+function templateInner(
+  strings: TemplateStringsArray,
+  exprs: any[],
+  escape: ((arg: string) => string) | undefined,
+) {
+  let text = "";
   for (let i = 0; i < Math.max(strings.length, exprs.length); i++) {
     if (strings.length > i) {
-      result += strings[i];
+      text += strings[i];
     }
     if (exprs.length > i) {
-      result += templateLiteralExprToString(exprs[i]);
+      const expr = exprs[i];
+      text += templateLiteralExprToString(expr, escape);
     }
   }
-  return result;
+  return text;
 }
 
-function templateLiteralExprToString(expr: any, escape?: (arg: string) => string): string {
+function templateLiteralExprToString(expr: any, escape: ((arg: string) => string) | undefined): string {
   let result: string;
   if (expr instanceof Array) {
     return expr.map((e) => templateLiteralExprToString(e, escape)).join(" ");