aetar - Online in the Cloud

PROGRAM:

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.

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