PKGBUILD

Yap adopts the PKGBUILD format from Arch Linux as its single package specification. One PKGBUILD produces .deb, .rpm, .pkg.tar.zst, or .apk packages depending on the target distribution.

Why PKGBUILD

Most packaging systems require distribution-specific spec files -- a .spec for RPM, debian/ directory trees for deb, APKBUILD for Alpine, and so on. Maintaining these in parallel for the same software is repetitive and error-prone.

PKGBUILD solves this by providing a minimal, readable format that describes what to build and how, without tying you to a single package manager:

• One file, all distros -- a single PKGBUILD replaces multiple spec formats.
• Simple shell syntax -- variables, arrays, and functions. No DSL to learn.
• Directives for differences -- where distros diverge (dependency names, paths), append __<directive> to override per target instead of maintaining separate files.
• Battle-tested -- the format powers the entire Arch User Repository (AUR) with tens of thousands of packages.

How Yap Extends It

Yap is compatible with the upstream PKGBUILD format and adds a few things on top:

• Directives -- target-specific overrides (depends__apt, depends__yum, pkgdesc__ubuntu_noble). See Directives.
• Cross-distro scriptlets -- preinst(), postinst(), prerm(), postrm() work across deb, rpm, and pacman. RPM also supports pretrans() and posttrans().
• Embedded interpreter -- Yap parses and executes PKGBUILDs with a built-in shell interpreter. Bash is not required on the build host.
• sha256sums / sha512sums -- hash type is inferred from the length of the hex string (64 or 128 characters).
• Custom variables, arrays, and helper functions (since v1.48) -- user-defined variables and arrays are automatically available in all build functions. Custom functions (any function not recognized as a standard PKGBUILD field) are treated as helpers and injected into build scripts. Helper functions referenced by install scriptlets (preinst, postinst, etc.) are automatically included in the scriptlet with transitive dependency resolution.

Subsections

• Format -- PKGBUILD syntax (strings, arrays, functions)
• PKGBUILD Spec -- Complete field and function reference
• Variables -- Built-in variables, custom variables, and helper functions
• Directives -- Distro-specific overrides

Further Reading

• Arch Wiki -- PKGBUILD
• Arch Wiki -- Creating packages