The program "ge_header" will do what you want. Sample output
ge_header ./AFNI_sample_01/SPGR_anat/I.019
-----------------------------------
File ./AFNI_sample_01/SPGR_anat/I.019
nx=256 ny=256 skip=7904 swap=YES compressed=NO bits-per-pixel=16
dx=0.9375 dy=0.9375 dz=1.1 zoff=-30.8 orient=RLAP xoff=120 yoff=120 TR=0.0123s TE=5.3ms
In this example, the slice offset is "zoff=-30.8".
bob cox