New comment by leahneukirchen on mblaze repository https://github.com/leahneukirchen/mblaze/issues/208#issuecomment-843920131 Comment: No, this is intentional. Some mblaze tools check if input is a tty and do some useful default behavior then. ``` If no msgs are specified, mscan reads filenames from the standard input, or scans the mails in the current sequence if used interactively. ``` You can use `mscan :` instead.