De fetchmail(1)
( man 1 fetchmail
):
Aumentando a verbosidade da saída:
-v | --verbose
Verbose mode. All control messages passed between fetchmail and the
mailserver are echoed to stdout. Overrides --silent. Doubling this
option (-v -v) causes extra diagnostic information to be printed.
Sobre a depuração para o syslog:
The --syslog option (keyword: set syslog) allows you to redirect status and
error messages emitted to the syslog(3) system daemon if available. Mes-
sages are logged with an id of fetchmail, the facility LOG_MAIL, and priori-
ties LOG_ERR, LOG_ALERT or LOG_INFO. This option is intended for logging
status and error messages which indicate the status of the daemon and the
results while fetching mail from the server(s). Error messages for command
line options and parsing the .fetchmailrc file are still written to stderr,
or to the specified log file. The --nosyslog option turns off use of sys-
log(3), assuming it’s turned on in the ~/.fetchmailrc file, or that the -L
or --logfile <file> option was used.
Espero que ajude!