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  • Ferret Users Guide
    • Users Guide Index
    • Commands Reference
    • 1. Introduction
    • 2. Data Set Basics
    • 3. Variables & Expressions
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    • 5. Animations & Gif Images
    • 6. Customizing Plots
    • 7. Handling String Data Symbols
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    • 9. Computing Environment
    • 10. Converting to NetCDF
    • 11. Writing External Functions
    • Glossary
    • Appendix A: Functions
    • Appendix B: PPLUS Guide
    • Appendix C: Ferret-Specific PPLUS Enhancements
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    • Ferret Tour
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    • COADS Tour
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    • Use OPeNDAP
    • Ferret binary read demo
  • PyFerret
    • PyFerret Downloads and Install ../../faq/ferret-faqs.html
    • What is PyFerret?
    • Why use PyFerret?
    • PyFerret for the Ferret user
    • PyFerret command syntax: quick-start notes
    • PyFerret for the Python user
    • Graphics in PyFerret ?
    • New Ferret functionality
    • PyFerret Python functions and constants
    • PyFerret Python objects and methods
    • Ferret external functions in Python
    • Ferret Fortran external functions
    • PyFerret metadata-and-data dictionaries
  • OPeNDAP
    • OPeNDAP usage in Ferret
    • Use OPeNDAP Demo
    • Test OPeNDAP

COMMAND FORMAT



3.1 THE COMMANDS

The basic format for PPLUS commands is:

COMM[/Q1/Q2 ... ][,arg1,arg2,arg3...][,sarg1,sarg2...]

where COMM is the PPL command. The numeric arguments arg1,arg2,... may be numbers in any fortran format (e.g. 1.E-5, -6, 10.23) or blank. The character string arguments sarg1,sarg2,... must begin with a non-numeric character string or be enclosed in quotes ("), i.e., "100". If the numeric or character string arguments are blank, the input is considered null and the default is used. Where all numeric arguments are to be defaulted, they may be omitted entirely (i.e., blank entries need not be made).

PPLUS commands may have optional qualifiers (Q1, Q2 etc...). The format for qualifiers is "/value" or "/novalue" for true or false, respectively.

All parameters must be separated by commas or blanks, except null entries which must have separating commas. Null entries are allowed except where noted in the specific command description.

Note that if you use commas, a blank followed by a comma will be interpreted as a null entry.

Example:

PPL AXLEN 2 , 1 ! Is interpreted as PPL AXLEN 2(, null)
PPL AXLEN 2, 1 ! Is interpreted as PPL AXLEN 2,1
PPL AXLEN 2 1 ! Is interpreted as PPL AXLEN 2,1

Commands can be continued on sequential lines by inserting a "-" (minus sign) at the end of the line to be continued.

All commands/parameters may be entered upper or lower case. Conversion to upper case is performed automatically when required.