flog (file logger) is a small C program that reads input from STDIN and writes
to a file, optionally adding timestamps. If SIGHUP is received, the file will
be reopened, allowing for log rotation (see newsyslog(8)). The log file will
only be reopened if flog detects that rotation has occurred (i.e., the old file
is gone or the inode has changed). flog is extremely small (a memory footprint
of less than 500 bytes). It also protects you from running out of disk space;
if that happens, the logfile will be truncated and a warning generated. This
could save you from waking up to pager beeps in the middle of the night.