SCUBA_PREFIX

In general, the initial stages of data reduction involve data taken on the same night. Typing in the full name of demodulated data files every time an observation is to be analysed is somewhat tedious and it would be much simpler if only the observation number was required.

Two pieces of information are required to spcify the file associated with a particular observation:

1. The observation number
2. The constant prefix of the data file

The SCUBA_PREFIX environment variable can be used to inform SURF of the form of the fixed prefix. Data files of the form prefix_dem_nnnn can be accessed by observation number (nnnn) so long as SCUBA_PREFIX is set to prefix (the _dem_ is added automatically).

Also, if the full path name is specified for SCUBA_PREFIX, DATADIR is not required. As an example, data in /scuba/observe/19971015/dem can be accessed by number either by setting

% setenv DATADIR /scuba/observe/19971015/dem
% setenv SCUBA_PREFIX 19971015

or by just setting SCUBA_PREFIX:

% setenv SCUBA_PREFIX /scuba/observe/19971015/dem/19971015

Note that the current directory is not searched in the second case (since the software adds the prefix before trying to load the file). The scusetenv command can be used to set this variable (this command is especially useful when reducing data at the Joint Astronomy Centre as DATADIR is also set correctly).