Open and View .chm Files on Linux (Ubuntu / Debian /Fedora)

The .chm file type is a “Microsoft Compressed HTML Help” file in a proprietary format for online help files. Linux and UNIX generally don’t come with native .chm support, but the functionality can easily be added. There are a number of solutions available, which I’ll outline below:

chm conversion

One option is to simply convert the .chm file to a more usable format, like .pdf. Most Linux distributions will come with a native .pdf viewer so conversion will allow you to use an existing application to view the information included in a .chm file. The most common conversion utility is chm2pdf. To install this application, use your favorite package manager, as shown below:

Ubuntu / Debian

sudo apt-get install chm2pdf

Fedora / CentOS

sudo yum install chm2pdf

The basic syntax for this utility is chm2pdf input_file output_file

GNOME .chm viewers

Another option is to install a native GNOME application to view .chm files. There are two such options, one is the gnochm utility and the other is chmsee. To install one of these applications, use your favorite package manager, as shown below:

Ubuntu / Debian

sudo apt-get install gnochm

sudo apt-get install chmsee

Fedora / CentOS

sudo yum install gnochm

sudo yum install chmsee

I have had much better luck with the second, chmsee. The gnochm utility crashes on me randomly, where chmsee has been very reliable.

KDE .chm viewers

There are a few options for KDE users as well. One option is to install a new application, and another is to use a plugin for Okular. I’ll outline each below.

First, you can try the utility kchmviewer. This is a native KDE application to open and view .chm files.
Second, you can add extra functionality to your existing viewer, Okular. You can install either of these using your preferred package manager, as shown below:

Ubuntu / Debian

sudo apt-get install kchmviewer

sudo apt-get install okular-extra-backends

Fedora / CentOS

sudo yum install kchmviewer

sudo yum install okular-extra-backends

Generic X viewers

For those looking for something a little more desktop-environment-agnostic, you might want to try xchm. This can be installed using the same methods outlined above:

Ubuntu / Debian

sudo apt-get install xchm

Fedora / CentOS

sudo yum install xchm

Conclusion

As a GNOME user I have had the best luck with chmsee. It feels very native and all of the .chm files I have opened are very well formatted. Navigation is easy, font style and size are easily readable as well.

I’d be interested in hearing what other options are out there. While it isn’t everyday that Linux users run into .chm files, when we do it is nice to have good solutions available.