Merging many flv files in a big file (avi format)

I was facing with problem from many days ... i had many files in flv format downloaded from youtube or others (through keepvid.com)

also i had linux on my system (UBUNTU) ... so i got these work around to create a singe copy by merging all those clips..

Step1 : change all the clips in avi format.

do : ffmpeg -i your_file.flv your_file.avi

to install ffmpeg do "sudo apt-get install ffmpeg"

This way change all the flv files into avi files ...

Step2 : merge all the avi files into single file.

do : avimerge -o destination.avi -i souce1.avi source2.avi .... sourceN.avi

to install avimerge do "sudo apt-get install transcode"