minirotate has been designed to be as simple as possible, while being useful. - it should be tool that works with other tools to achieve final result - all configuration should be in done on command line - runnable from cron by multiple users at once - no state kept between invocations - solid construction, no loose ends, hence static typing - reasonably fast, but don’t optimize anything prematurely
Most common application of file rotation is log rotation. This isn’t the only one though. minirotate was written for backup files in the first place.
We first use tar to create temporary tarball.
`$ tar -cjf /tmp/foo.tar.bz2 /home/foo`
Then we use `minirotate` to move our logs to final place:
`$ minirotate /tmp/foo.tar.bz2 /mnt/backup/foo`
foo.tar.bz2 is renamed according to default file pattern.
We can also specify our own pattern like this:
`$ minirotate -p '{basename}-{modtime %d-%m-%Y-%H_%M_%S}{ext}' /tmp/foo.tar.bz2 /mnt/backup/foo`
The format pattern and functions (denoted by curly braces {}) are explained below.
We will rotate files in place:
`minirotate --move -p '{filename}.{modtime %d-%m-%Y}' /var/log/bar/ /var/log/bar/old`
Note that we --move files instead of default --copy action.
`minirotate '' /var/log/bar --max-files=10`
This works because '' is regarded as special, empty input that is simply skipped.
If unsure how certain operation will work use --dry-run switch. It won't operate but instead print operations that would be made. Note that this isn't entirely true: if we move some files in the first stage, we will usually affect the rotate stage. It's still useful to see how program understands our input.
From manpage: logrotate - rotates, compresses, and mails system logs
minirotate won’t: - send mail to anyone - compress anything - use any extra configuration - schedule itself - have 60+ configuration options
In general, if you want to do something more complex you will usually write a script for it. It’s fine. That’s their purpose: glueing several tools together.
minirotate --help will print brief explenation of command line switches:
Usage: minirotate [OPTIONS] SOURCE [SOURCE..] DESTINATION
-h, -? --help show help
-V --version show version
--show-defaults show program defaults
-p PATTERN --pattern=PATTERN pattern for final files
-m --move set copy mode to 'move'
-c --copy set copy mode to 'copy'
--min-files=NUM minimum number of files to keep
--max-files=NUM maximum number of files to keep
--max-age=NUMSEC maximum age of files to keep
--dry-run don't remove or copy any files
Most are pretty straitforward. Files will be taken from multiple sources and put into destination. Aditionally we can use ’’ (empty string) to denote null input source.
When rotating files the rules are applied in order: - Delete too old files (by mod time) - Delete exceeding files (by filename) - Undelete to keep minimum count of files (by filename)
Pattern syntax is simple: everything that is not enclosed by ‘{}’ is kept verbatim. Inside ‘{}’ we can place calls to functions, which are called for each file individually.
We don’t allow nested ‘{}’. If one does do this, the result is undefined - and we don’t have to report error in this case. Sorry.
If the function takes arguments (for now only “modtime” does so) there can be arbitraly number of spaces between the function name and arguments. After the first non-space argument the rest of spaces are included verbatim, so the resulting filename can have spaces.
So far there are only 4 of them:
file : full filename, and that excludes directories in filepath (examples: iexplore.exe, music.mp3, acpi.log, backup.tar.bz2)ext : take file extension including leading dot (examples: .exe, .mp3, .log, .bz2)basename : same as file but drop extension (examples: iexplore, music, acpi, backup.tar)modtime tfmt : formats file modification time according to format string tfmt