@BeginModule
@NewPage
@Name      = Select
@Title     = Select fields
@Section   = Selection
@Class     = Selection
@Arguments = ifiles ofile
@Operators = select delete

@BeginDescription
This module selects some fields from @file{ifiles} and writes them to @file{ofile}.
@file{ifiles} is an unlimited number of input files. All input files need to have 
the same structure with the same variables on different timesteps.
The fields selected depends on the chosen parameters. Parameter is a comma
separated list of key-value pairs.
@EndDescription
@EndModule


@BeginOperator_select
@Title     = Select fields
@Parameter = params

@BeginDescription
Selects all fields with parameters in a user given list.
@EndDescription
@EndOperator


@BeginOperator_delete
@Title     = Delete fields
@Parameter = params

@BeginDescription
Deletes all fields with parameters in a user given list.
@EndDescription
@EndOperator


@BeginParameter
@Item = name
STRING  Comma separated list of variable names
@Item = param
STRING  Comma separated list of parameter identifiers
@Item = code
INTEGER Comma separated list of code numbers
@Item = ltype
INTEGER Comma separated list of GRIB level types
@Item = levidx
INTEGER Comma separated list of index of levels
@Item = level
FLOAT   Comma separated list of vertical levels
@Item = hour
INTEGER Comma separated list of hours
@Item = day
INTEGER Comma separated list of days
@Item = month
INTEGER Comma separated list of months
@Item = year
INTEGER Comma separated list of years
@Item = timestep
INTEGER Comma separated list of timesteps
@EndParameter


@BeginExample
Assume you have 3 inputfiles. Each inputfile contains the same variables for a different time period.
To select the variable T,U and V on the levels 200,500 and 850 from all 3 input files, use:
@BeginVerbatim
   cdo select,name=T,U,V,level=200,500,850 ifile1 ifile2 ifile3 ofile
@EndVerbatim
@EndExample
