Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MSDOS)?

Because some stdio's set error and eof flags that need clearing. The POSIX module defines clearerr that you can use. That is the technically correct way to do it. Here are some less reliable workarounds:

  1. Try keeping around the seekpointer and go there, like this: 

        $where = tell(LOG);
    seek(LOG, $where, 0);

  2. If that doesn't work, try seeking to a different part of the file and then back.

  3. If that doesn't work, try seeking to a different part of the file, reading something, and then seeking back.

  4. If that doesn't work, give up on your stdio package and use sysread.