updates

kernel/bin/head

@@ -0,0 +1,38 @@
+/** Shared helpers for drive-resident /bin scripts (prepended before each command). */
+function bareStdin(ctx) {
+  return typeof ctx.shellStdin === 'string' ? ctx.shellStdin : ''
+}
+
+async function run(ctx, argv) {
+  const vfs = ctx.vfs
+  let n = 10
+  let start = 1
+  if (argv[1] === '-n' && argv[2]) {
+    n = parseInt(argv[2], 10) || 10
+    start = 3
+  } else if (argv[1] && /^-\d+$/.test(argv[1])) {
+    n = parseInt(argv[1].slice(1), 10) || 10
+    start = 2
+  }
+  const files = argv.slice(start).filter((a) => a !== '--')
+  const take = (s) => {
+    const lines = s.split('\n')
+    const out = lines.slice(0, n).join('\n')
+    ctx.console.log(
+      out + (out && !out.endsWith('\n') && lines.length > n ? '\n' : '')
+    )
+  }
+  if (!files.length) {
+    take(bareStdin(ctx))
+    return
+  }
+  for (const f of files) {
+    const buf = await vfs.readFile(f)
+    if (!buf) {
+      ctx.console.error('head: ' + f + ': No such file')
+      continue
+    }
+    if (files.length > 1) ctx.console.log('==> ' + f + ' <==')
+    take(ctx.b4a.toString(buf))
+  }
+}