NAME
tbl-dctrl - generate tabular representations of data in dctrl format
SYNOPSIS
tbl-dctrl [ options ] -c column-specification ... [ filename ] ...
tbl-dctrl --version
tbl-dctrl --help
DESCRIPTION
tbl-dctrl creates tabular representations of data given to it in Debian
control file format.
By default, tbl-dctrl reads the whole database, looking for the longest
entry in each requested column; it then outputs a table, with borders
and column titles, where each column is just wide enough to fit the
longest entry. Most of this behaviour can be customized as described
below.
A column is requested by specifying the -c (--column) switch with a
column specification. The simplest kind of a column specification
consists solely of the name of a field. In such a case, tbl-dctrl will
include in the output a column whose title is the literal column
specification and whose data is drawn from fields with that name. At
least one column must be requested.
There are two optional additions one can make to a column
specification. Prefixing the field name with some text followed by an
equality sign (for example, -c ’Package name=Package’) modifies the
column in such a way that the text before the equality sign is used as
the column title, while the text after the equality sign is used as the
name of the field from which data is drawn. One can also append a
colon followed by a positive whole number to the field name. In such a
case, the number after the colon specifies the width of the column.
These two additions can be used separately or together. If there are
more than one colon, the last one is significant. If there are more
than one equals sign, the first one is significant. Other colons and
equals signs are used simply as data. Note that the whole column
specification must be given to tbl-dctrl as one argument, so if it
contains spaces, it must be quoted for the shell.
If all requested columns have a specified width, tbl-dctrl will produce
output immediately, not waiting for the whole input to be read in.
OPTIONS
-d DELIMITER, --delimiter=DELIMITER
Instead of drawing nice borders to the table, use the specified
delimiter string to delimit columns in a row.
-H, --no-heading
Do not print a table heading (column titles).
-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
tbl-dctrl will read its input from the files named on the command line,
in the specified order. A file called - represents the program’s
standard input stream. If no files are named, the program behaves as
if - alone had been named, that is, input is read from the standard
input stream.
STDIN
The standard input stream may be used as input as specified above in
the OPERANDS section.
INPUT FILES
All input to tbl-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
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).
When input is read from multiple files, a record separator is implicit
between two adjacent files.
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 a
tabular representation of the input database restricted to the
specified fields. Logically, the output is a table; when the -d option
is used, this table is represented simply by separating columns in each
row by the specified delimiter; when the option is not used, a frame is
drawn around the table. The order of the columns is the same as the
order of the column specifications on the command line.
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
The following command line pipe outputs a table of all packages, with
their maintainer data, sorted by the maintainer data, that have no
content:
% grep-available -FInstalled-Size --eq 0 | sort-dctrl -kMaintainer - |
tbl-dctrl -cPackage -cMaintainer
SEE ALSO
ara(1), apt-cache(1), dpkg(8), dpkg-awk(1), dpkg-query(1),
grep-dctrl(1), sort-dctrl(1)
AUTHOR
The tbl-dctrl program and this manual page were written by Antti-Juhani
Kaijanaho.