I have a question on how to use cat. where does it belong? Thanks.

I need to join 2 avi files. cat man instructions deal with text files, and don't seen to work on avi files.

The manual page shows the basic usage of cat; you could also check the manual page for bash and scroll to the section titled "Here Documents" for some slightly more complex usages.

cat is short for "concatenate", and is often used to read files, like:

shell$ cat filename # this will read the file "filename" to the screen.

For the manual, type:

shell$ man cat

Or, if there's some particular usage case that you are not understanding, please post us an example, or provide more detail of exactly what you wish to know about cat.

Sasha

PS - you should create a more informative title for your thread(s) -- an example would be:
"Please tell me about the `cat` command-- how to use it?"
You can edit this thread title by clicking EDIT, then click GO-ADVANCED, and fix up the title

Cheers!

Is this the way to reply??? I'm still trying to find out how to use this site. If so:
need to join 2 avi files, man pages deal only in text files. (??) and the example does not work for me,

Hello,
append the content of file2 to file1 :
echo the content of file1 and the content of file2 on stdout :
cat works fine, but don't expect to have a nice avi file when concatenating two of them. Chances are they are out of sync (think of the headers etc).
From http://linuxclues.blogspot.com/2008/...avi-files.html, to join two avi files with mencoder :

Yes, that's a pretty good way to reply, I thought.

And it was effective: it caused you to provide more detail about what exactly you're trying to do, AND it educated you about an aspect of using this site

Sasha

The real answer is that it all depends on the file type. Some formats like mp3 have an atomic structure, where each individual subsegment contains all the playback information necessary for that segment. This kind of format can be easily combined by cat without affecting playback ability (though you may have issues with things like metadata tags).

But AFAIK the avi container isn't one of those. It uses a single header at the beginning of the file to define the playback parameters for the whole file. You generally have to rebuild the whole container if you edit the media inside it. This means you need to use a dedicated video editor, such as mencoder or ffmpeg.

O.K. Now I've posted a dum question, gotten very good answers, so now how do I respond to whomever has been kind enough to provide me with the needed help, or "yep, I tried that, didn't work" response. ?? Is this block the correct place for this?? Or: Where's the operating manual for navigasting this site?

Is this the spot for answering a particular person who has offered help? If so: thanks, I got mencoder installed, (I think) but when I tried to use it per instructions I got the "command not found " message.
is reboot required?

In Tutorials/LinuxQuestions.org/How to Use LinuxQuestions.org.
That is there :
http://www.linuxquestions.org/linux/...xQuestions_org
you'll find some reading about that.

David the H. has in his signature :

Just keep posting in th thread unless you feel the topic has changed so much athat a new thread is approriate. In this case you started asking about cat and it looks like the topic is changing to mencoder and ffmpeg.

Regards an LQ user guide I don't know of one. Just by lurking you'll see how things are done and the regular posters are pretty friendly and will keep you pointed in the right direction. Relax. Enjoy

To see if mencoder is installed
in a terminal type
To install mencoder, this depends on your distribution.
Which didtribution are you using ?