Uhhmmm... I've heard of this stuff somewhere... For example, I wanted to show the output of the ls command and df command in a single output to screen or file... How would I do that? Thanks!

There are many ways of "combining" Linux commands. You want to output two commands to the same file, that's an easy one.

ls >somefiledf >>somefile

A single > will redirect output to a file, erasing whatever was there. A double >> will append to a file. You can now use less or cat on that file to display it. Or you could use a subshell. When using a subshell, all output of the commands run in the subshell can be piped as one. Here's how you can run these two commands, write their output to a file and view them in less all at once.

(ls; df) | tee somefile | less

Lots of things you can do, lots of different ways you can do it. I recommend reading the Bash man page if you're interested in stuff like this.

Quote: Original post by Tradone
piping using the | operator is one widely used method.

and I don't know the deal with the &'s
but for example,
make & make install
is a common method as well.

That isn't correct. A single & will start a background task. A double && is a boolean operator. "make && make install" will run make, and if it succeeds (returns zero), it will run make install. This takes advantage of the short-circuit behavior of the && operator. In this case, since he's running ls and df (the return value of either is not really relevant), neither & nor && will help.

A single & will run the process in the background.
foo && bar will run bar only if foo succeeded (zero exit code) (short-circuit evaluation of 'and').
foo || bar will run bar only if foo failed (non-zero exit code) (short-circuit evaluation of 'or').