[docs] some updates

docs/source/cli.rst

@@ -4,10 +4,20 @@
 Command Line Interface
 ======================
 
+The following options can be used when starting **lnav**.  There are not
+many flags because the majority of the functionality is accessed using
+the :code:`-c` option to execute :ref:`commands<commands>` or
+:ref:`SQL queries<sql-ext>`.
+
 -h  Print these command-line options and exit.
 -H  Start lnav and switch to the help view.
--C  Check the configuration for any errors and exit.
--c  Execute the given command.  This option can be given multiple times.
+-C  Check the given files against the configuration, report any errors, and
+    exit.  This option can be helpful for validating that a log format is
+    well-formed.
+-c cmd  Execute the given lnav command, SQL query, or lnav script.  The
+   argument must be prefixed with the character used to enter the prompt
+   to distinguish between the different types (i.e. ':', ';', '|').
+   This option can be given multiple times.
 -f path  Execute the given command file.  This option can be given multiple times.
 -I path  Add a configuration directory.
 -i  Install the format files in the :file:`.lnav/formats/` directory.
@@ -21,7 +31,7 @@ Command Line Interface
 -t  Prepend timestamps to the lines of data being read in on the standard
     input.
 -w path  Write the contents of the standard input to this file.
--V  Print the version of lnav
+-V  Print the version of lnav.
 -q  Do not print the log messages after executing all of the commands.
 
 Examples

docs/source/howitworks.rst

@@ -0,0 +1,6 @@
+
+.. _howitworks:
+
+How It Works
+============
+

docs/source/index.rst

@@ -15,6 +15,8 @@ Contents:
    :maxdepth: 2
 
    intro
+   usage
+   howitworks
    cli
    ui
    hotkeys

docs/source/usage.rst

@@ -0,0 +1,50 @@
+
+.. include:: kbd.rst
+
+.. _usage:
+
+Usage
+=====
+
+This chapter contains an overview of how to make use of **lnav**.
+
+Viewing Files
+-------------
+
+The files to view in **lnav** can be listed on the command-line or passed to the
+:ref:`:open<open>` command.  If the path is a directory, all of the files in the
+directory will be opened and the directory will be monitored for files to be added
+or removed.  A
+`glob pattern <https://en.wikipedia.org/wiki/Glob_(programming)>`_ can also be
+used to watch for files that match the pattern.  The files that are found will be
+scanned to identify their file format.  Files that match a log format will be
+collated and displayed in the LOG view.  Plain text files can be viewed in the
+TEXT view, which can be accessed by pressing |ks| t |ke|.
+
+Log message parsing is the base that many of the other features mentioned in this
+chapter are built upon.  Messages are matched against regular expressions defined
+in log format definitions.  When **lnav** first opens a file, it will cycle through
+all of the known formats and try to match the beginning lines in the file against
+the patterns.  When a match is found, 
+
+
+Searching
+---------
+
+
+
+
+Filtering
+---------
+
+To reduce the amount of noise in a log file, **lnav** can filter out log messages
+based on the following criteria:
+
+* Regular expression match
+* Time
+* Log level
+
+Search Tables
+-------------
+
+