How do I open .001 .002 .003 file extension files?

In our day to day life we have to use internet extensively. Recently I had tough time to open somefile.avi.001, somefile.avi.002, somefile.avi.003 etc. I was not aware of how to open those files. Actually I had downloaded a movie. But it had 4 parts. These parts were named as the above.

I did research all day with the help of Google search. I executed lot of system commands. Some of them even messed up my system. Finally I got some useful information from the Google search.

Actually that files were split files. By splitting the big file they give some additional extension as .001, .002, .003 etc. To make that to a single file you have to use program to join those files.

Here I have used “hjsplit” software for that. I joined those for files with that tool.After the whole day research I have found out the way to open the file.