1) COMMENT: first of all, you have to create a file named "atoms.dat" in one directory. This file looks like:
atoms.dat
with one atom type per line, and in the same order you have them in your POSCAR file.
2) As soon as you have done it, copy this source:
posxcry.pl
BUT YOU HAVE TO CHANGE THE PATH THAT APPEARS IN LINE 29 (/home/lbellarosa/Lavoro/IRMOF-Zn/atoms.dat) with
the path where you put your atoms.dat file (i.e./home/nlopez/Trabajo/atoms.dat).
3) Now you can run the script typing:
pos2xcry.pl CONTCAR/POSCAR