NAME
join-dctrl - perform relational join on data in dctrl format
SYNOPSIS
join-dctrl [ options ] filename filename
join-dctrl --version
join-dctrl --help
DESCRIPTION
join-dctrl performs a relational join operation on data given to it in
Debian control file format.
A join field must be specified using either the switches -1 and -2 or
the switch -j. Conceptually, the program creates all ordered pairs of
records that can be formed by having a record from the first file as
the first member of the pair and having a record from the second file
as the second member of the pair; and then it deletes all such pairs
where the join fields are not equal. Effectively, each of the input
files is treated as a relational database table.
Every input file must be in ascending order on its join field; this
allows the program to work fast. The sort-dctrl(1) program can be used
to make it so.
OPTIONS
-1 FIELD, --1st-join-field=FIELD
Specify the join field of the first input file.
-2 FIELD, --2nd-join-field=FIELD
Specify the join field of the second input file.
-j FIELD, --join-field=FIELD
Specify a common join field for all files.
-a FIELDNO,--unpairable-from=FIELDNO
Specify that unmatched paragraphs from the first (if 1 is given)
or the second (if 2 is given) file are printed.
-o FIELDSPEC, --output-fields=FIELDSPEC
Specify which fields are included in the output. Fields are
separated by commas (more than one -o option can be used, too).
Each field is specified in the format fileno.field in which
fileno is the ordinal number of the input file from which the
field is drawn (either 1 or 2), and field gives the name of the
field to use. As a special case, simple 0 can be used instead
of fileno.field to refer to the common value of the join fields.
The name of the field (not including the file number) is used in
the output as the name of the field. However, a different name
for output purposes can be specified by suffixing the field
specification by a colon and the preferred visible name.
For example, the option -o 0,1.Version:Old-Version,2.Version
specifies that the first field in any output record should be
the join field, the second field should be Old-Version drawing
its data from the Version field of the first input file, and the
third field should be Version drawing its data from the field
with the same name in the second input file, and these are the
only fields in an output record.
If no -o option is given, all fields of all the records being
joined are included in the output.
-l LEVEL, --errorlevel=LEVEL
Set debugging level to LEVEL. LEVEL is one of "fatal",
"important", "informational" and "debug", but the last may not
be available, depending on the compile-time options. These
categories are given here in order; every message that is
emitted when "fatal" is in effect, will be emitted in the
"important" error level, and so on. The default is "important".
-V, --version
Print out version information.
-C, --copying
Print out the copyright license. This produces much output; be
sure to redirect or pipe it somewhere (such as your favourite
pager).
-h, --help
Print out a help summary.
OPERANDS
join-dctrl will treat each file named on the command line as a
relational database table. A file called - represents the program’s
standard input stream. Currently, exactly two files must be named.
STDIN
The standard input stream may be used as input as specified above in
the OPERANDS section.
INPUT FILES
All input to join-dctrl is in the format of a Debian control file.
A Debian control (dctrl) file is a single table of a semistructured
database stored in a machine-parseable text file. Such a table
consists of a set of records; each record is a mapping from field names
to field content. Textually, records are separated by empty lines,
while each field is encoded as one or more nonempty lines inside a
record. A field starts with its name, followed by a colon, followed by
the field content. The colon must reside on the first line of the
field, and the first line must start with no whitespace. Subsequent
lines, in contrast, always start with linear whitespace (one or more
space or tab characters).
Each input file must be in the ascending order of its join field.
ENVIRONMENT VARIABLES
The standard locale environment, specifically its character set
setting, affects the interpretation of input and output as character
streams.
ASYNCHRONOUS EVENTS
Standard Unix signals have their usual meaning.
STDOUT
All output is sent to the standard output stream. The output is in the
format of a Debian control file, described above in the INPUT FILES
section. The output will be in the ascending order of the join field,
if that field is included in the output.
OUTPUT FILES
There are no output files.
EXIT STATUS
This utility exits with 0 when successful. It uses a nonzero exit code
inconsistently when an error is noticed (this is a bug).
CONSEQUENCES OF ERRORS
In case of errors in the input, the output will be partially or
completely garbage. In case of errors in invocation, the program will
refuse to function.
EXAMPLES
Suppose that a file containing data about binary packages for the AMD64
architecture contained in the Debian etch (4.0) release, section main,
is in the current directory and named Packages. Suppose that we are
currently on a Debian system. Suppose further that the current
directory does not contain files named stat and pkg. The following
commands gives, for each package currently installed and available in
Debian etch (4.0), its currently installed version (as Old-Version) and
the version in etch (as New-Version):
$ sort-dctrl -kPackage /var/lib/dpkg/status > stat
$ sort-dctrl -kPackage Packages > pkg
$ join-dctrl -j Package \
-o 0,1.Version:Old-Version,2.Version:New-Version \
stat pkg
SEE ALSO
grep-dctrl(1), sort-dctrl(1), tbl-dctrl(1)
AUTHOR
The join-dctrl program and this manual page were written by Antti-
Juhani Kaijanaho.
join-dctrl(1)