McIDAS Learning Guide
Version 2006

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Getting Started - Basic Concepts (Continued)

Commands

McIDAS applications are command-driven, which makes the system very flexible. There are two basic command formats in McIDAS:

Positional parameters are words, numbers, or letters that further define a command. You must enter positional parameters in the exact order specified in the command format. It is not always necessary to use every positional parameter. If you want to specify the default value for a positional parameter, enter an X in its place.

You can also add keywords to the command to further clarify a command function. Keywords are optional and their order in the command is not important, provided they follow the positional parameters and precede quoted text.

Some arguments (positional parameters, keyword parameters) like dates, latitudes, and longitudes must conform to certain formats. The ARGHELP command can be used to get a listing of these argument formats.

Most keywords are command specific; however the seven global keywords below can be used with any McIDAS command.

The DEV= keyword specifies the destination device of text output generated by a command. The FONT= keyword specifies the font for drawing text on the image window. The MCCompress= keyword specifies the data compression method the ADDE remote server uses when sending requested data to the workstation. The PAN= keyword specifies the frame panel number for displaying output or reading frame information. The TCOL= keyword specifies the text output color for text written to the text window. The TWIN= keyword specifies the destination text frame for text message output. The VIRT= keyword specifies a virtual graphics number to write the graphics output to. See the McIDAS User's Guide or run the GLOBKEY command for more information.

A sample command line is shown below:

ZA 3 20 C POS=200 200 "McIDAS
| \ / | |
command parameters keyword quoted text

To run single letter commands, simultaneously press the Alt key and the letter key, or type the letter and press Enter. Below is an example of the format for single letter commands in the Learning Guide.

Press:  Alt A

To run multiple letter commands, type the command and press Enter. This Learning Guide assumes you will always press Enter after typing the command. Below is an example of the command format in the Learning Guide.

Type:  CW 1 3

This means you should type CW 1 3 and then press Enter. You can have multiple spaces between parameters and keywords.

A command line can contain several commands. To concatenate commands, type a semicolon between the commands. For example:

Type:  IMGDISP MYDATA/IMAGES.8000 3;LS 1-3

When multiple commands are entered on the command line, each command is run in the order it is listed. The first command must finish before the next command can begin.

Some commands have a quote (") field that indicates all text following the quote belongs to that command. When concatenating commands with quote field, you need to replace the double quote with a left brace ({) and place a right brace before the semicolon to surround the quote field. For example, typing:

SKE X 00:00 1 "SFCLIST KMSN 12;ERASE F 1
would enter the commands SFCLIST KMSN 12 and ERASE F 1 into the command scheduler file to run at a later time (00 UTC in this example). But, typing the following:
SKE X 00:00 1 {SFCLIST KMSN 12};ERASE F 1

would enter the command SFCLIST KMSN 12 into the command scheduler file to run at 00 UTC, but run ERASE F 1 immediately to erase the graphics on frame 1.

Several keys are available for editing the command line. Listed below are command line editing keys and their functions.

Key Function
Home moves the cursor to the beginning of the line
End moves the cursor to the end of the line
Insert toggles the insert typing mode
Delete deletes the character over the cursor
Backspace deletes the character to the left of the cursor
Right/Left arrows moves the cursor one character to the right or left
Tab, Shift Tab moves the cursor one parameter to the right or left
Enter runs the command
Esc erases the command from the command line and places the cursor at the beginning of the line
Alt ? displays an abbreviated help for the current command in the text frame
& and ^ recalls a command if the command line is empty; & recalls the previous command from a list of the last 100 commands entered;^ scans the call list in the opposite direction
Ctrl LeftMouseButton prints the latitude and longitude of the cursor position on the command line

Command Stack

Command Mode-entered commands are maintained in a list that can be scanned forward or backward. In McIDAS-X, the number of commands to remember is specified in the .mcidasrc file, with a default of 1000. If the command line is empty, you can scan backward through the list of commands using the ampersand (&) key and scan forward through the list using the caret (^) key. These recalled commands can be reviewed, re-executed, or edited and then executed. This feature is very useful when learning to use commands. You can easily add and/or change parameters and keywords on previously executed commands without having to retype the entire command.

Command Helps

The online helps provide an abbreviated description of the McIDAS commands. For a complete description of each command, see the McIDAS User's Guide.

You can also get information on the status of your session using the F command. The output includes the number and size of frames, current and opposite frame numbers, current loop bounds, K and L toggle states, cursor type, cursor size, cursor color and its position on the frame as shown below. 

 
   Video Status for Your Workstation
                            Frames(s)
                            ---------
 Number Available                  6
 Current                           1   (Opp =  4 )
 Loop Bounds                    1 to   6
 Visible (K & W toggle)          Yes / Yes
 Looping (L toggle)               No
 Cursor parameters: Size =   31 /   31         Type = Xhair
         Center position =  206 /  396         Color = RED
 
 Image frames   1 -   6     with imbedded graphics    are  480 BY  640

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