1 Concepts GILDAS Grenoble Image and Line Data Analysis System This package consists in three different parts : 1. A number of utilities named "tasks", which are basically non interactive programs with a parameter file. A given program (e.g. "PROG") is located in GILDAS_RUN:PROG. The parameter file is prepared by commands RUN and SUBMIT of several programs. 2. Four interactive program named VECTOR, DISPLAY, GRAPHIC and OVERLAY. VECTOR is able to execute the tasks mentionned before by means of the commands SUBMIT and RUN. DISPLAY is in addition able to make colour bit-map display of the images on an image processor. GRAPHIC is able to make graphic display of the images (contour, etc...). OVERLAY is a superset of DISPLAY and GRAPHIC. 3. GFITS, an interactive FITS to GDF (Grenoble Data Format used to store images) translator. This help summarizes help on various tasks now available. The interactive programs have their own HELP files in GAG_HELP. 1 END