grep-dctrl

grep-dctrl [OPTIONS] [FIELD...] [PATTERN...] [FILE...]

-s, --show-only
    Output only the matching field, not the whole paragraph.

-v, --invert-match
    Invert the sense of matching, to select non-matching paragraphs.

-i, --ignore-case
    Ignore case distinctions in patterns and data.

-e PATTERN, --regexp=PATTERN
    Use PATTERN as a regular expression. Can be used multiple times to specify multiple patterns.

-f FILE, --file=FILE
    Obtain patterns from FILE, one per line.

-F, --fixed-strings
    Interpret PATTERNs as fixed strings, not regular expressions.

-X, --extract
    Extract and output matched fields, including their field names and values.

-l, --files-with-matches
    Suppress normal output; instead print the name of each input file from which output would normally have been printed.

-L, --files-without-matches
    Suppress normal output; instead print the name of each input file from which no output would normally have been printed.

-h, --no-filename
    Suppress the prefixing of filenames on output when multiple files are searched.

-n, --paragraph-number
    Prefix each output paragraph with the 1-based paragraph number within its input file.

-d, --debian-control
    Treat input as a Debian control file. This is often the default behavior due to its primary purpose.

grep-dctrl is a specialized command-line utility for searching Debian control files, such as those found in /var/lib/dpkg/status, Packages.gz, or Sources.gz files. Unlike the standard grep, which operates on lines of text, grep-dctrl understands the paragraph-and-field structure inherent in Debian control files. This allows users to search for patterns within specific fields (e.g., Package, Description, Depends) or across all fields of a control paragraph.

It is an invaluable tool for system administrators, package maintainers, and developers within the Debian ecosystem. It enables quick and precise queries on package metadata, helping to find packages based on their description, dependencies, maintainer, or any other information stored in their structured control records. grep-dctrl is part of the dctrl-tools suite and leverages Perl regular expressions for powerful pattern matching.

grep-dctrl is specifically designed for the Debian control file format. While it can process any plain text formatted with blank-line-separated paragraphs and colon-separated fields, its primary utility is within the Debian package management context.
Being a Perl script, its performance characteristics might differ from native C programs like GNU grep, especially on extremely large unstructured files, though this is rarely a practical limitation for its intended use case.

grep-dctrl can read structured data from standard input (via a pipe) or from one or more specified FILE arguments. If no FILE is provided, it defaults to reading from standard input.

If one or more FIELD arguments are provided before the PATTERNs, grep-dctrl will restrict its search to only those named fields. If no fields are specified, the search is performed across all fields within each paragraph.

Unlike traditional grep, grep-dctrl primarily operates on 'paragraphs' (records separated by blank lines) rather than individual lines. By default, it outputs the entire paragraph that contains a match, making it easier to view complete package records.

grep-dctrl is a core utility within the dctrl-tools package, which provides a set of powerful command-line tools for processing Debian control files. Its development is closely tied to the Debian project's needs for efficiently querying and manipulating package metadata, serving as a foundational tool for package management operations.

grep(1), dpkg-query(1), apt-cache(8), dctrl-tools(1)