ghc-pkg(1)

✨ ghc-pkg ✨

okay bestie, buckle UP 💖 this is the GHC Haskell Cabal package manager — yes that's the whole vibe of the ghc-pkg(1) page, and we're gonna go through it together, no skimming, no cap. ✨

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🌸 NAME 🌸

ghc-pkg — GHC Haskell Cabal package manager 🎀

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🦋 SYNOPSIS 🦋

ghc-pkg action [OPTION]...

that's it. action, then options. slay. 💅

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💜 DESCRIPTION 💜

so like. a package is a library of Haskell modules that the compiler knows about. ghc-pkg is the lil tool that lets you add them to or remove them from a package database. by default it messes with the system-wide package database, but you can also act on the user's local package database, or on another file you specify entirely. options options options. ✨

to make a package available for ghc, you use ghc-pkg to register it. unregistering it removes it from the database. also — and this is the cute part — packages can be hidden, which makes ghc ignore the package by default without uninstalling it. exposing a package makes a hidden package available again. and on top of all that, ghc-pkg has a whole bunch of commands to query the package database. 👑

where a package name is required, you can name the package in full including the version number (e.g. network-1.0), or without the version number. naming a package without the version number matches all versions of the package, and the specified action gets applied to all the matching packages. a package specifier that matches all versions of the package can also be written pkg-*, so it's clearer that multiple packages are being matched. 💖

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🎀 ACTIONS 🎀

• register filename|- — Register the package using the specified installed package description. 📥
• update filename|- — Register the package, overwriting any other package with the same name. 🔄
• unregister pkg-id — Unregister the specified package. 👋
• expose pkg-id — Expose the specified package. 🌞
• hide pkg-id — Hide the specified package. 🙈
• list [pkg]... — List registered packages in the global database, and also the user database if --user is given. If a package name is given, all the registered versions will be listed in ascending order. Accepts the --simple-output flag. 📋
• dot — Generate a graph of the package dependencies in a form suitable for input for the graphviz tools. For example, to generate a PDF of the dependency graph: 🌈

dot  tred  dot -Tpdf >pkgs.pdf

• find-module module — List registered packages exposing module module in the global database, and also the user database if --user is given. All the registered versions will be listed in ascending order. Accepts the --simple-output flag. 🔍
• latest pkg-id — Prints the highest registered version of a package. ⬆️
• check — Check the consistency of package dependencies and list broken packages. Accepts the --simple-output flag. 🩺
• describe pkg — Give the registered description for the specified package. The description is returned in precisely the syntax required by ghc-pkg register. 📝
• field pkg field — Extract the specified field of the package description for the specified package. Accepts comma-separated multiple fields. 🧐
• dump — Dump the registered description for every package. This is like ghc-pkg describe '*', expect that it is intended to be used by tools that parse the results, rather than humans. 🤖
• recache — Regenerate the package database cache. This command should only be necessary if you added a package to the database by dropping a file into the database directory manually. By default, the global DB is recached; to recache a different DB use --user or --package-conf as appropriate. ♻️

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💅 OPTIONS 💅

when you ask it to modify a database (register, unregister, update, hide, expose, and also check), ghc-pkg modifies the global database by default. specifying --user makes it act on the user database, or --package-conf can be used to act on another database entirely. when multiple of these options are given, the rightmost one is used as the database to act upon. 👀

commands that query the package database (list, latest, describe, field) operate on the list of databases specified by the flags --user, --global, and --package-conf. if none of these flags are given, the default is --global --user. ✨

• --user — Use the current user's package database. 🫶
• --global — Use the global package database. 🌍
• -f FILE, --package-conf=FILE — Use the specified package config file. 📁
• --global-conf=FILE — Location of the global package config. 🗺️
• --force — Ignore missing dependencies, directories, and libraries. 💪
• --force-files — Ignore missing directories and libraries only. 🗂️
• -g, --auto-ghc-libs — Automatically build libs for GHCi (with register). 🔧
• -?, --help — Display a help message and exit. ❓
• -V, --version — Output version information and exit. 🏷️
• --simple-output — Print output in easy-to-parse format for some commands. 🧾
• --names-only — Only print package names, not versions; can only be used with list --simple-output. 🏷️
• --ignore-case — Ignore case for substring matching. 🔤

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🌈 ENVIRONMENT VARIABLES 🌈

• GHC_PACKAGE_PATH — The GHC_PACKAGE_PATH environment variable may be set to a :-separated list of files containing package databases. This list of package databases is used by ghc and ghc-pkg, with earlier databases in the list overriding later ones. This order was chosen to match the behaviour of the PATH environment variable; think of it as a list of package databases that are searched left-to-right for packages. 👑

If GHC_PACKAGE_PATH ends in a separator, then the default user and system package databases are appended, in that order. e.g. to augment the usual set of packages with a database of your own, you could say: 🫶

export GHC_PACKAGE_PATH=$HOME/.my-ghc-packages.conf:

To check whether your GHC_PACKAGE_PATH setting is doing the right thing, ghc-pkg list will list all the databases in use, in the reverse order they are searched. 🔄

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🍓 FILES 🍓

Both of these locations are changed for Debian. Upstream still keeps these under /usr. Some programs may refer to that, but look in /var instead. 🚨

• /var/lib/ghc/package.conf — Global package.conf file. 📄
• /var/lib/ghc/package.conf.d/ — Directory for library specific package.conf files. These are added to the global registry. 📂

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🧚 SEE ALSO 🧚

ghc(1), runghc(1), hugs(1). 💖

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👑 AUTHOR 👑

This manual page was written by Kari Pahula <kaol@debian.org>, for the Debian project (and may be used by others). 🫶

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okay that's the whole thing bestie, no notes, iconic behavior, periodt. 💅✨

2010-01-27 — ghc-pkg(1) — that's the source, the version, and the date, and that's a wrap 🎀💖