rpm is the package format used on RedHat Enterprise (RHEL), Fedora, CentOS, and a number of other Linux distributions.
You may be familiar with tools such as dnf and yum for installing packages from repositories. The package files that these tools install are rpms.
fpm supports input and output for rpms. This means you can read an rpm and convert it to a different output type (such as a dir or deb). It also means you can write an rpm.
For the sample command reading an rpm as input and outputting a debian package:
fpm -s rpm -t deb file.rpmThe the argument is used as a file and read as an rpm.
Create a package with no files but having dependencies:
% fpm -s empty -t rpm -n example --depends nginx
Created package {:path=>"example-1.0-1.x86_64.rpm"}We can now inspect the package with rpm's tools if you wish:
% rpm -qp example-1.0-1.x86_64.rpm -i
Name : example
Version : 1.0
Release : 1
Architecture: x86_64
Install Date: (not installed)
Group : default
Size : 0
License : unknown
Signature : (none)
Source RPM : example-1.0-1.src.rpm
Build Date : Wed 20 Oct 2021 09:43:25 PM PDT
Build Host : snickerdoodle.localdomain
Relocations : /
Packager : <jls@snickerdoodle>
Vendor : none
URL : http://example.com/no-uri-given
Summary : no description given
Description :
no description givenfpm supports rpm as both an input and output type (-s and -t flags), so you can use this to modify an existing rpm.
For example, let's create an rpm to use for our example:
% fpm -s empty -t rpm -n example
Created package {:path=>"example-1.0-1.x86_64.rpm"}Lets say we made a mistake and want to rename the package:
% fpm -s rpm -t rpm -n newname example-1.0-1.x86_64.rpm
Created package {:path=>"newname-1.0-1.x86_64.rpm"}And maybe the architecture is wrong. fpm defaulted to x86_64 (what fpm calls "native"), and we really want what rpm calls "noarch":
% fpm -s rpm -t rpm -a noarch newname-1.0-1.x86_64.rpm
Created package {:path=>"newname-1.0-1.noarch.rpm"}