I created a pkg file with the productbuild utility and I'd like to see its content. How can I do that?
I'm under MacOS 10.9.5.
You could extract your package into temporary directory with pkgutil.
pkgutil --expand pkg-path dir-path
Expand the flat package at pkg-path into a new directory specified by dir-path.
There is also very good third party tool called Pacifist, by CharlesSoft. You can view the contents of the package without extracting it.
Update
Inside pkg archive (which is a xar archive) you may encounter following files:
The Mac OS X Installer uses a file system "bill of materials" to determine which files to install, remove, or upgrade. A bill of materials, bom, contains all the files within a directory, along with some information about each file. File information includes: the file's UNIX permissions, its owner and group, its size, its time of last modification, and so on. Also included are a checksum of each file and information about hard links. [man bom]
You may list the contents of bom file with lsbom command. And create the file with mkbom.
This xml file contains general information about the package.
This is a gziped cpio archive. You may extract its contents to current directory with tar command:
$ tar -xf Payload
Or extract to specified directory dir-path:
$ tar -C dir-path -xf Payload
Optionally you may only list the contents of the Payload archive with:
$ tar -tf Payload
You should be able to recreate the archive from dir-path with:
$ tar --format cpio -czf Payload dir-path