NAME
aetar - remotely distribute a change via tar
SYNOPSIS
aetar -Send [ option... ]
aetar -Receive [ option... ]
aetar -List [ option... ]
aetar -Help
aetar -VERSion
DESCRIPTION
The aetar command is used to send and receive change sets via tar(1) to
facilitate geographically distributed development.
The basic function is to reproduce a change, so a command like
aetar -send | aetar -receive
may be used to clone a change, though less efficiently than aeclone(1).
The file format used is an ordinary gzip(1) compressed tar(1) archive.
SEND
The send variant takes a specified change, or baseline, and constructs
a distribution package containing all of the source file contents. No
change meta-data is included.
It is not necessary for the recipient to have the aetar(1) command. It
is possible to use the regular tar xzf command to extract the files
from the archive.
Options
The following options are understood by the send variant:
-BaseLine
This option may be used to specify the source of a project,
rather than a change.
-Add_Path_Prefix string
This option may be used to specify a path prefix to be added to
every filename in the archive. This means that when the
archive is unpacked, it will all be placed in the one
directory.
-Change number
This option may be used to specify a particular change within a
project. See aegis(1) for a complete description of this
option.
-COMPATibility version-number
This option may be used to specify the version of aetar(1)
which will be receiving this change set. This information is
used to select which features to include in the data, and which
to omit. By default, the latest feature set will be used.
-compression-algorithm name
This option may be used to specify the compression to be used.
They are listed on order of compression effeciency.
none Use no compression (not always meaningful for all
commands).
gzip Use the compression used by the gzip(1) program.
bzip2 Use the compression used by the bzip2(1) program.
More compression algorithms may be added in the future.
-COMPress
This option is deprecated in favour of the -comp-alg=gzip or
-comp-alg=bzip2 options.
-No_COMPress
This options is deprecated in favour of the -comp-alg=none
option.
-DELta number
This option may be used to specify a particular delta in the
project’s history to copy the file from, rather than the most
current version. If the delta has been given a name (see
aedn(1) for how) you may use a delta name instead of a delta
number. It is an error if the delta specified does not exist.
Delta numbers start from 1 and increase; delta 0 is a special
case meaning “when the branch started”.
-DELta_Date string
This option may be used to specify a particular date and time
in the project’s history to copy the file from, rather than the
most current version. It is an error if the string specified
cannot be interpreted as a valid date and time. Quote the
string if you need to use spaces.
-DELta_From_Change number
This option may be used to specify a particular project delta
from its change number.
-Entire_Source
This option may be used to send the entire source of the
project, as well as the change source files. This is the
default.
-Partial_Source
This option may be used to send only source files of a change.
-Include_Build
This option may be used to send also build files.
-Not_Include_Build
This option may be used to send only source (source, test,
config but not build) files. This is the default.
-Output filename
This option may be used to specify the output file. The output
is sent to the standard output by default.
-Project name
This option may be used to select the project of interest.
When no -Project option is specified, the AEGIS_PROJECT
environment variable is consulted. If that does not exist, the
user’s $HOME/.aegisrc file is examined for a default project
field (see aeuconf(5) for more information). If that does not
exist, when the user is only working on changes within a single
project, the project name defaults to that project. Otherwise,
it is an error.
RECEIVE
The receive variant takes a tarball and creates an Aegis change (see
aenc(1)) to implement the change within. Files are added to the change
(see aenf(1), aecp(1), aerm(1), aent(1)) and then the file contents are
unpackaged into the development directory.
It is not necessary for the sender to have the aetar(1) command. It is
possible to use the regular tar czf command to create the the tarball.
You may want to use the tardy(1) command to manipulate the filenames
before extraction.
File Names
It is common for tar files generated to distribute open source projects
to contain a path prefix.
-Remove_Path_Prefix string
This option may be used to explicitly specify path prefixes to
be removed, if present. It may be specified more than once.
-Remove_Path_Prefix number
Strip the smallest prefix containing num leading slashes from
each file name found in the patch file. A sequence of one or
more adjacent slashes is counted as a single slash.
If you have a complex project directory structure, from time to time
people may send you tarballs relative to a sub-directory, rather than
relative to the project root.
-Add_Path_Prefix string
This option may be used to specify the path of a project sub-
directory in which to apply the tarball.
Notification
The aetar command invokes various other Aegis commands. The usual
notifications that these commands would issue are issued.
Options
The following options are understood by the receive variant:
-Change number
This option may be used to choose the change number to be used,
otherwise one will be chosen automatically.
-DELta number
This option may be used to specify a particular delta in the
project’s history to copy the file from, just as for the
aecp(1) command. You may also use a delta name instead of a
delta number.
-DIRectory path
This option may be used to specify which directory is to be
used. It is an error if the current user does not have
appropriate permissions to create the directory path given.
This must be an absolute path.
Caution: If you are using an automounter do not use ‘pwd‘ to
make an absolute path, it usually gives the wrong answer.
-EXCLude
This option may be used to exclude certain files in the tarball
from consideration.
You can also add more exclusions using the project_specific
field of the project configuration, using the aetar:exclude
attribute listing file names to exclude separated by spaces.
-Exclude_Auto_Tools
This option may be used to exclude files common to tarballs of
open source projects which used GNU Autoconf or GNU Automake.
This is triggered by the presence of configure.ac, configure.in
or Makefile.am files. This only works for simple projects,
more complex projects will need to use the project exclude
attributes.
You can set this automatically using the boolean aetar:exclude-
auto-tools attribute in the project_specific field of the
project configuration file.
-Exclude_CVS
This option may be used to exclude files common to CVS
repositories, which implement the repository functions, rather
than contain source code. It will also look inside .cvsignore
files for additional files to ignore.
You can set this automatically using the boolean aetar:exclude-
cvs attribute in the project_specific field of the project
configuration file.
-File filename
Read the change set from the specified file. The default is to
read it from the standard input. The filename ‘-’ is
understood to mean the standard input.
If your system has libcurl(3), and Aegis was configured to use
it at compile time (this is the default if it is available) you
will also be able to specify a Uniform Resource Locator (URL)
in place of the file name. The relevant data will be
downloaded. (The -Verbose option will provide a progress bar.)
-Project name
This option may be used to select the project of interest.
When no -Project option is specified, the AEGIS_PROJECT
environment variable is consulted. If that does not exist, the
user’s $HOME/.aegisrc file is examined for a default project
field (see aeuconf(5) for more information). If that does not
exist, when the user is only working on changes within a single
project, the project name defaults to that project. Otherwise,
it is an error.
-Trojan This option may be used to treat the change set as if it had a
Trojan horse attack in it.
-No_Trojan
This option may be used to treat the change set as if it
definitely does not have a Trojan horse attack in it. Use with
extreme care. You need to have authenticated the message with
something like PGP first and know the the author well.
Security
Downloading a tarball and automatically committing it to the baseline
without checking it would be a recipe for disaster. A number of
safeguards are provided:
· The file sare unpacked into a new change. You need to edit the
change description. You need to uncopy unchanged files. You need to
difference the change. You need to build and test the change. This
ensures that a local reviewer validates the change before it is
committed, preventing accidental or malicious damage.
· The use of authentication and encryption systems, such as PGP and
GPG, are encouraged. However, it is expected that this processing
will occur after aetar --send has constructed the package and before
aetar --receive examines and acts on the package. Verification of
the sender is the surest defense against trojan horses.
· Automatic sending and receiving of packages is supported, but not
implemented within the aetar command. It is expected that the aetar
command will be used within shell scripts customized for your site
and its unique security requirements. See the Aegis User Guide for
several different ways to do this.
· The more you use Aegis’ test management facilities (see aent(1) and
aet(1)) the harder it is for an inadequate change to get into the
baseline.
LIST
The list variant can be used to list the contents of a tarball without
actually unpacking it first.
Options
The following options are understood by the list variant:
-File filename
Read the change set from the specified file. The default is to
read it from the standard input. The filename ‘-’ is
understood to mean the standard input.
If your system has libcurl(3), and Aegis was configured to use
it at compile time (this is the default if it is available) you
will also be able to specify a Uniform Resource Locator (URL)
in place of the file name. The relevant data will be
downloaded. (The -Verbose option will provide a progress bar.)
-Output filename
This option may be used to specify the output file. The output
is sent to the standard output by default. Only useful with
the -List option.
OPTIONS
The following options to this command haven’t been mentioned yet:
-Help
This option may be used to obtain more information about how to
use the aetar program.
See also aegis(1) for options common to all aegis commands.
All options may be abbreviated; the abbreviation is documented as the
upper case letters, all lower case letters and underscores (_) are
optional. You must use consecutive sequences of optional letters.
All options are case insensitive, you may type them in upper case or
lower case or a combination of both, case is not important.
For example: the arguments "-project, "-PROJ" and "-p" are all
interpreted to mean the -Project option. The argument "-prj" will not
be understood, because consecutive optional characters were not
supplied.
Options and other command line arguments may be mixed arbitrarily on
the command line, after the function selectors.
The GNU long option names are understood. Since all option names for
aetar are long, this means ignoring the extra leading ’-’. The
"--option=value" convention is also understood.
FILE FORMAT
The file format re-uses existing formats, rather than introduce
anything new. This means it is possible to extract the contents of a
package even when aetar is unavailable.
· The source files and other information is stored as a normal Unix
tar(1) archive.
· On sending, the tarball is compressed using the GNU gzip format.
Typically primary source files are ASCII text, resulting in
significant compression. (This is optional.)
On receiving, if the tarball is compressed it will be automagically
uncompressed, detection is automatic, you do not need to do this
yourself.
EXIT STATUS
The aetar command will exit with a status of 1 on any error. The aetar
command will only exit with a status of 0 if there are no errors.
ENVIRONMENT VARIABLES
See aegis(1) for a list of environment variables which may affect this
command. See aepconf(5) for the project configuration file’s project_
specific field for how to set environment variables for all commands
executed by Aegis.
COPYRIGHT
aetar version 4.24.3.D001
Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Peter
Miller
The aetar program comes with ABSOLUTELY NO WARRANTY; for details use
the ’aetar -VERSion License’ command. This is free software and you
are welcome to redistribute it under certain conditions; for details
use the ’aetar -VERSion License’ command.
AUTHOR
Peter Miller E-Mail: millerp@canb.auug.org.au
/\/\* WWW: http://www.canb.auug.org.au/~millerp/