logging
syslog(3)
syslog(3) is the C logging library in unix. It writes to /log/<filename> by
default.
logger(1)
logger(1) is the standard log command in unix. It's the shell interface to
syslog(3) and provides a way to redirect stdout / stderr to the system
logger. It's included in most Unix distributions by default.
logger(1) does not handle log rotation, as that is a different concern. All
it will do is log to the default system log. While this can be useful, when
using the ndjson format the additional information becomes useless.
example entry
Nov 3 11:57:23 localhost user.notice root: hello world!
links
logrotate(1)
logrotate is a tool that, well, rotates logs. "Rotating logs" is swapping
out log files for other log files, for example after a certain time limit
(every day) or when a file limit is hit.
logrotate(1) is developed by the Fedora team, and is not included in Busybox
and OS X by default. Here's some stuff it can do:
- rotate logs when a file size is reached
- continue to write information to new file after rotating the old file
- compress the rotated files
- specify compression options for rotated log files
- rotate the old log files with the date in the filename
- execute custom shell scripts immediately after log rotation
- remove older rotated log files
files used
/usr/sbin/logrotate # the logrotate command itself
/etc/logrotate.conf # main configuration file
/etc/logrotate.d/* # per-program configuration
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