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Is logrotate hiding somewhere on OSX, or is there an equivalent? It's not in /usr/sbin.

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Why the downvote? – Steve Bennett Jan 24 '12 at 0:40
I dunno why you got a downvote, so I upvoted it. I think it's a good question. – Tom O'Connor Jan 24 '12 at 0:45
I notice there is newsyslog, but that's not quite the same and requires root. – Steve Bennett Jan 24 '12 at 1:05
Can logrotate be ported, i wonder. – Tom O'Connor Jan 24 '12 at 1:28
check /etc/periodic, I believe that log rotation is by default implemented as a set of shell scripts in there. Also look at newsyslog (/etc/newsyslog.d and man page) for a way to do it based on file size. – malcolmpdx Jan 24 '12 at 4:56
up vote 10 down vote accepted

Based on Brian Armstrong's answer, here's something with a little more explanation and a correction. This handles the log created by postgres on OSX installed by Homebrew. Located at /etc/newsyslog.d/postgresql.conf:

# logfilename                           [owner:group]      mode count size(KB)  when  flags [/pid_file]                            [sig_num]
/usr/local/var/postgres/postgresql.log  :                  600  2     2048      *     J     /usr/local/var/postgres/ 

This will rotate the log file when it reaches 2MB in size, keep 2 archives (for a total of 6MB storage used), and bzip2-compress the archives. It will notify the postgres process to reopen the log files once rotated, which is necessary to get new log entries and to actually free the disk space without restarting the machine.

Important to note that size is in KB, not bytes.

You can test the config file (without affecting any files) using sudo newsyslog -nvv.

newsyslog documentation is located here: Also used:

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OS X has several ways to rotate/expire/etc its logs, depending on the type of log in question:

  1. For regular log files (i.e. text files that are continuously appended to), newsyslog can rotate them based on size or time, although it doesn't seem to have as many options as logrotate. It's configured by /etc/newsyslog.conf and /etc/newsyslog.d/* (generally, you should add files to /etc/newsyslog.d/ to add logs to its management list).
  2. OS X's syslog system is migrating from this plain-text format to database format, mainly in /var/log/asl/. I don't entirely understand this system yet, but this database seems to be purged by aslmanager, which is configured by /etc/asl.conf.
  3. For directories that have individual log "entries" added as separate files (mainly /Library/Logs/CrashReporter/), the files get purged by /etc/periodic/daily/100.clean-logs. Its policies (which directories to scan & how long to leave files) are configured in /etc/defaults/periodic.conf, but if you want to override/change them you should create /etc/periodic.conf.local and put your customizations there.

If what you want to rotate doesn't fit any of these models, you can add your own scripts to /etc/periodic/daily/ (which'll be run every morning at 3:15am), /etc/periodic/weekly/ (every saturday morning at 3:15am), or /etc/periodic/monthly/ (first of every month at 5:30am).

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newsyslog runs automatically on OSX, I use a config file like this in /etc/newsyslog.d/rails_apps.conf to keep my dev log files trimmed to 5MB

# logfilename                           [owner:group]   mode count size     when  flags [/pid_file] [sig_num]
/Users/barmstrong/code/**/log/*.log                     666  0     5242880  *     G
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size is in K, and a ":" is required for owner:group even if they're blank – Bryan Ash Jan 14 at 21:07

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