At first thought, I would use 3dTcat or 3dbucket in a loop, but you can also do it with this script that uses 3dcalc and duplicated sub-bricks in the sub-brick list.

I'm not sure exactly what you're trying to accomplish, but you might want to use a 1D text file instead of a 3D+time datasets. For info on using 1D files as input for 3D programs.

[afni.nimh.nih.gov]



#!/bin/tcsh
# multi_copy.csh
if ("$1" == '' || "$1" == "-help" || "$1" == "-h") then
echo "Usage: A script to create a 3D+time dataset by duplicating "
echo " the 0th sub-brick n times"
echo ""
echo " `basename $0` n-copies <dsetname>"
echo ""
echo "The output dataset is saved as dsetprefix_multi+orig"
echo ""
goto END
endif

set ncopies = $1

set dset = `@GetAfniPrefix $2`
set outdset = ${dset}_multi
set copylist = '0'

@ ncopies--
rm -f $outdset+orig.*
foreach copyi (`count 1 ${ncopies}`)
set copylist = `echo "${copylist},0"`
end

3dcalc -a ${2}."[${copylist}]" -prefix $outdset -expr a

END: