#!/bin/csh -f
#+
# wavelen -- set/show the wavelength on the current slider
#
# Purpose:
#	With no arguments, show the wavelength of the currently
#	installed grating.  With one argument, set the current grating
#	wavelength to the specified value.
#
# Usage:
#	wavelen [lambda]
# 
# Arguments:
#	lambda = wavelength to select, in Angstroms
# 
# Output:
#	Written to stdout
# 
# Restrictions:
# 
# Exit values:
#	 0 = normal completion
#	 1 = wrong number of arguments
#
# Example:
#
#-
# Modification history:
#	2002-Aug-26	GDW	Original version
#-----------------------------------------------------------------------

set buf = $0
set cmd = $buf:t
set usage = "Usage: $cmd [lambda]"

# verify args...
if ( $#argv > 1 ) then
  printf "$usage\n"
  exit 1
endif

# parse args...
if ( $#argv >= 1 ) then
    set lambda = $1
    shift
endif

# determine the current slider...
@ slider = `slider`
if ( $slider != 3 && $slider != 4 ) then
    printf "ERROR -- can only use this command when slider 3 or 4 is in\n"
endif

# set if lambda is defined, otherwise show...
if ( $?lambda ) then
    modify -s deimot g${slider}tltwav=$lambda
else
    show -s deimot -terse g${slider}tltwav
endif