join-dctrl

join-dctrl(1)               General Commands Manual              join-dctrl(1)

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 al-
       lows  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 fileno, --unpairable-from=fileno
              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  log  level to level.  level is one of fatal, important, in-
              formational and debug, but the last may not  be  available,  de-
              pending 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  rela-
       tional  database table.  A file called - represents the program's stan-
       dard 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 semistructured single-table database
       stored in a machine-parseable text file.  Such a database consists of a
       set of records; each record is a mapping from field names to field con-
       tent.  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  con-
       trast,  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  set-
       ting,  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  com-
       pletely  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 squeeze (6.0) 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 di-
       rectory does not contain files named stat and pkg.  The following  com-
       mands  gives, for each package currently installed and available in De-
       bian squeeze (6.0), its currently installed  version  (as  Old-Version)
       and the version in squeeze (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

AUTHOR
       The  join-dctrl  program  and  this  manual page were written by Antti-
       Juhani Kaijanaho.

SEE ALSO
       grep-dctrl(1), sort-dctrl(1), tbl-dctrl(1)

                                                                 join-dctrl(1)