--sort
From Open Babel
[Introduced in OpenBabel version 2.3.0]
The --sort option is used to output molecules ordered by the value of a descriptor:
babel infile.xxx outfile.xxx --sort desc
If the descriptor desc provides a numerical value, the molecule with the smallest value is output first. For descriptors which provide a string output the order is alphabetical, but for the inchi descriptor a more chemically informed order is used (e.g. "CH4" is before than "C2H6", "CH4" is less than "ClH" hydrogen chloride).
The order can be reversed by preceding the descriptor name with '~', e.g.
babel infile.xxx outfile.yyy --sort ~logP
As a shortcut, the value of the descriptor can be appended to the molecule name by adding a '+' to the descriptor, e.g.
babel aromatics.smi -osmi --sort ~MW+ c1ccccc1C=C styrene 104.149 c1ccccc1C toluene 92.1384 c1ccccc1 benzene 78.1118