grep-dctrl

grep-dctrl [options] expression [files ...]

-F field
    Search only in the specified field (e.g., Package, Version)

-s field
    Show only the specified field(s) in output

-n
    Prefix each line with record number

-N
    Prefix with 1-based record number

-v
    Invert match (show non-matching records)

-f file
    Read additional search fields from file

-P pattern
    Use Perl-compatible regex instead of POSIX

-r flags
    Regex flags (e.g., i for case-insensitive)

-m count
    Stop after matching count records

--exact
    Match whole field value exactly

--and
    Combine expressions with AND (default)

--or
    Combine with OR

--not
    Negate the expression

--quoting=style
    Output quoting: shell, csv, c, escape

--no-field-names
    Omit field names in output

-X chars
    Show substring starting after prefix chars

--help
    Display usage summary

--version
    Show version information

grep-dctrl is a specialized tool from the dctrl-tools package designed to query Debian package database files in control format, such as /var/lib/dpkg/status or /var/lib/apt/lists/*Packages. Unlike standard grep, it understands the structured format of Debian control files, where records consist of multi-line fields separated by blank lines. It allows efficient searching by field name, supports regular expressions, and can output specific fields or counts.

Key features include field-specific searches (-F), showing only certain fields (-s), exact matching, logical operators for complex queries, and options for output formatting like quoting styles. It's invaluable for package maintainers, sysadmins, and users querying installed packages, dependencies, versions, or descriptions without parsing files manually. By default, it searches all fields unless specified otherwise, making it faster and more precise than piping grep through dpkg commands.

Does not support multi-character field names with -F; assumes standard Debian control format. May be slower on very large files without field restriction. Perl regex (-P) requires Perl compatibility.

grep-dctrl -F Package '^apache' /var/lib/dpkg/status
grep-dctrl -s Maintainer,Version 'Status: install ok' /var/lib/dpkg/status

Typically /var/lib/dpkg/status, /var/lib/dpkg/available, or APT Packages lists. Reads from stdin if no files given.

Originally developed by Erik Andersen in 2001 as part of debtags tools, evolved into dctrl-tools by Frank Lichtenheld for Debian. Maintained in Debian since 2004 (version 2.0+), with ongoing updates for new regex features and Debian policy compliance. Widely used in Debian derivatives like Ubuntu.

grep(1), pgrep-dctrl(1), dpkg-query(1), dctrl(5)