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Tide closes in

Using the command line interface

The command line interface, tide, supports a number of modes that cannot be accessed with the interactive client.  It can run without X-windows, and unlike the interactive client, it can easily be invoked from shell scripts.

The minimal usage is simply to specify a location with -l.  The default mode is plain, and the default format is text: 

$ tide -l "anchorage, al"
Anchorage, Alaska
61.2383° N, 149.8883° W

2003-02-12  7:27 AM AKST   Moonset
2003-02-12  8:50 AM AKST   Sunrise
2003-02-12 10:19 AM AKST  10.72 feet  Low Tide
2003-02-12 11:34 AM AKST   Moonrise
2003-02-12  3:42 PM AKST  24.41 feet  High Tide
2003-02-12  5:37 PM AKST   Sunset
2003-02-12 11:00 PM AKST   1.95 feet  Low Tide
2003-02-13  5:31 AM AKST  25.51 feet  High Tide
2003-02-13  8:29 AM AKST   Moonset

If you use the same location a lot, you can set the environment variable XTIDE_DEFAULT_LOCATION to its name instead of using -l every time.

The non-interactive client supports most of the command line switches related to settings which are described in a later section.  (As a notable exception, the graph font cannot be changed.)  In addition, it supports the following.

-b "YYYY-MM-DD HH:MM"
Specify the begin (start) time for predictions using the ISO 8601 compliant format YYYY-MM-DD HH:MM, where hours range from 00 to 23.  The timestamp is in the local time zone for the location, or in UTC if the -z setting is engaged.  If clock mode is selected or if no -b is supplied, the current time will be used.  (Note Quirk #1)
-e "YYYY-MM-DD HH:MM"
Specify the end (stop) time for predictions in banner, calendar, alt. calendar, medium rare, plain, raw, or stats mode.  Does not apply in graph and clock modes:  the effective end time for graph and clock modes is entirely determined by the start time (-b), the width (-cw, -gw or -tw), and the aspect (-ga).  The format and time zone are the same as for -b.  If no -e is supplied, the end time will be set to four days after the begin time.  (Note Quirk #2)

When it matters, -b and -e ranges mean specifically "all t such that b ≤ t < e."

-f c|h|i|l|p|t|v
Specify the output format as CSV, HTML, iCalendar, LaTeX, PNG, text, or SVG.  See the modes page for legal modes and formats.  The default is text.
-l "Location Name"
Specify a location for tide predictions.  You get the first station where the name supplied with -l is a case-insensitive match with the beginning (or the entirety) of the station's name.  You can use the -l switch more than once if you want to specify multiple locations.
-m a|b|c|C|g|k|l|m|p|r|s
Specify mode to be about, banner, calendar, alt. calendar, graph, clock, list, medium rare, plain, raw, or stats.  See the modes page for legal modes and formats.  The default is plain.
-ml [-]N.NN(ft|m|kt)
Specify the mark level to be used in predictions.  The predictions will include the times when the tide level crosses the mark.  Not supported in clock mode.  Example usage: -ml -0.25ft
-o "filename"
Redirect output to the specified file (appends).
-s "HH:MM"
Specify the step interval, in hours and minutes, for raw or medium rare mode predictions.  The default is one hour.
-v
Print version string and exit.  Please note that versions marked as DEVELOPMENT versions are not really versioned; they are work in progress and will change without warning.

The interactive interface does not support all of these switches and options.  Refer to the previous page for a list of the options supported by the interactive interface.

XTide understands the following syntactic shortcuts:

Some shorthand forms are ambiguous.  For example, -lw5 could mean "set the line width to 5" (-lw 5) or it could mean "load the location named w5" (-l w5).  If this happens, you will get an error and will need to spell out what you meant.

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