tbl-dctrl - Online in the Cloud

PROGRAM:

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. If no -c options
are given, tbl-dctrl will use all fields in the input in the order in which they first
appear.

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 log 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

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