[gmx-users] SS from xpm file

[Nguyen Hoang Phuong]

Dear All,

after performing do_dssp, I got the file like ss.xpm which looks like

"SSSSSSSSSSSS~~~S~~~~~SSSSSSSSSSSS~STSSSSSSSTTTTTSTST~~~~S~~~S~~",
"SSSSSSSSSSSSS~~SSSSSSSSSSSSSSSSSSSSTSSSSSSSTTTTTSTSTSSSSSSSSSSS",

each line contains the information about secondary structures of one
residue. I would like to compute the percentages of the structures S, T
etc. for each residue. To this end I have to count how many letters S, T
of each line. Do you know how to performing this counting?

Many thanks in advance,

Phuong