# Introduction to Sequences

The Chapter Tour Through xmh and this one have mentioned sequences more than once. Let's summarize that information here -- and add to it.

A sequence is a list of message numbers, just like an MH sequence. It's used for grouping messages temporarily or permanently. When you view the sequence in your Table of Contents, you'll only see those particular messages from the folder. The other messages are still in the folder; they're just not shown. Note the following:

- Every folder and subfolder has its own sequence named `all`. Naturally enough, this sequence has all messages in the folder.
- On most systems, each folder can have up to 26 sequences -- not counting the `all` sequence. (Older versions of MH, and MH running on small systems, has a limit of 10 sequences.) When you make a sequence, it stays with the folder until you delete the sequence.
- Each sequence in a folder has its own entry on the `Sequence` menu. The selected sequence has a check mark by it. The Figure below shows that `mailquestions` is currently selected, but I'm about to select `all` (the sequence will be selected after I let go of the mouse button).

Figure: Selecting a sequence (all)

There are two ways to select a sequence:

1. If you select the sequence with the first mouse button, that changes the selected sequence but doesn't view it in the Table of Contents.

   When you use `Open Sequence`, a listing of the messages opens in the Table of Contents. If you're adding a message to a sequence, though, you won't want to open it.

2. The accelerator is selecting the sequence with the second mouse button. That selects the sequence and views it in the Table of Contents.

To make a sequence, use the `Pick` command -- then, if you want, you can use the `Add to Sequence` and `Remove from Sequence` commands to move messages into or out of the sequence. First, let's take a look at the way to make sequences: `Pick`.