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.

-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

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:	pmiller@opensource.org.au
/\/\*	WWW:	http://miller.emu.id.au/pmiller/