shtool-rotate - Online in the Cloud

PROGRAM:

NAME

shtool-rotate - GNU shtool log file rotation

SYNOPSIS

shtool rotate [-v|--verbose] [-t|--trace] [-f|--force] [-n|--num-files count] [-s|--size
size] [-c|--copy] [-r|--remove] [-a|--archive-dir dir] [-z|--compress [tool:]level]
[-b|--background] [-d|--delay] [-p|--pad len] [-m|--mode mode] [-o|--owner owner]
[-g|--group group] [-M|--migrate cmd] [-P|--prolog cmd] [-E|--epilog cmd] file [file ...]

DESCRIPTION

This command rotates a logfile file by subsequently creating up to count (optionally
compressed) archive files of it. Archive files are named "file.number[compress-suffix]"
where number is the version number, 0 being the newest and "count-1" the oldest.

A rotation step consists of the following steps

1. remove last archive file 2. shift archive file numbers 3. create archive file 0 from
file 4. truncate/recreate file

OPTIONS

The following command line options are available.

-v, --verbose
Display some processing information.

-t, --trace
Enable the output of the essential shell commands which are executed.

-f, --force
Force silent creation of archive directory if it does not exists. Also skip missing
intermediate logfiles in the rotation step. Default is to exit with error in both
cases. FIXME

-n, --num-files count
Create count archive files. Default is 10.

-s, --size size
Only rotate if logfile exceeds size. The argument size can be specified also with the
trailing units "K" (kilo), "M" (mega) or "G" (giga). The "prolog" and "epilog" are
only executed if rotation actually takes place.

-c, --copy
Copy file to archive then truncate original. The default is to move file to archive.

Unless an application reopens its logfile it will continue to write to the same file.
In the default move case the application will write to the archive which it had
previously opened as file. In the copy case the application will write to the original
file. The drawback of the copy approach is that logfile entries are lost when they are
written to file between the execution of the copy and the truncation operation. The
drawback of the move approach is that the application needs to detect the move or must
be triggered to reopen its log (i.e. through epilog).

-r, --remove
Removes file after rotation instead of providing a new empty file.

-a, --archive-dir dir
Specify the archive directory. Default is to create archives in the same directory as
file is located.

-z, --compress [tool:]level
Enables compression of archive files with compression level level By default, the
tools bzip2(1), gzip(1) and compress(1) are searched for in $PATH, but one also can
override this by prefixing the compression level with one of the three particular tool
names.

-b, --background
Enable background compression.

-d, --delay
Delays the compression of archive file number 0. This is useful if ``-c'' is not used,
because an application might continue to write to archive file 0 through an already
open file handle.

-p, --pad len
Enables padding with leading zeros in the number part of the filename
"file.numbercompress-suffix". The default padding len is 1. This is interesting if
more than 10 archive files are used, because it leads to still sorted directory
listings.

-m, --mode mode
The file mode applied to the created files, see chmod(1). Setting mode to "-" skips
this step and leaves the operating system default which is usually based on umask(1).
Some file modes require superuser privileges to be set. Default is 0755.

-o, --owner owner
The file owner name or id applied to the created files, see chown(1). This option
requires superuser privileges to execute. Default is to skip this step and leave the
operating system default which is usually based on the executing uid or the parent
setuid directory.

-g, --group group
The file group name or id applied to the created files, see chgrp(1). This option
requires superuser privileges to execute to the fullest extend, otherwise the choice
of group is limited on most operating systems. Default is to skip this step and leave
the operating system default which is usually based on the executing gid or the parent
setgid directory.

-M, --migrate cmd
Execute a "migration" command just before the archive file number count-1 is removed
from the filesystem. The specified cmd receives the archive filename as command line
argument.

-P, --prolog cmd
Execute a "prolog" command before the rotation step. Useful in conjunction with -s.

-E, --epilog cmd
Execute a "epilog" command after the rotation step. Useful in conjunction with -s.

EXAMPLE

# shell script
shtool rotate -n10 -s1M -zbzip2:9 -d -r /var/log/ap.access.log
shtool rotate -n5 -s128K -zbzip2:9 -d -r /var/log/ap.error.log
apachectl graceful

HISTORY

The GNU shtool rotate command was originally written by Ralf S. Engelschall
<[email protected]> in 2001 for GNU shtool. Its development was prompted by the need to
have a flexible logfile rotation facility in the OpenPKG project.

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