[dajiaohuang]

The regex-capture example reads and displays text.txt, but its ambr command instead targets test.txt. In a directory containing just the shown text.txt, the command reports a missing file and leaves the contents unchanged.

Use text.txt consistently. Verified in an isolated directory: the original command reports the missing test.txt; the corrected command changes aaa bbb\n into exactly aaa bbb aaa bbb\n, as shown in the README. No other files are created or changed.