Hi Lennart,
I have a question about running your script "gen-prot.inp", which I downloaded from your website.

I define the environment variables as you recommend:
setenv CHM_HOME /v/estor1/home/charmm/c30b2/
setenv CHM_STREAM /v/estor3/home/usr/Temp/CHARMM_Tutorial/Scripts/

and run the script and get the following error:
CHARMM> open unit 21 read form name 4pti-a.pdb
VOPEN> Attempting to open::4pti-a.pdb::
OPNLGU> Unit 21 cannot be opened as 4PTI-A.PDB

***** LEVEL 0 WARNING FROM *****
***** "OPEN" not possible.

The 4pti-a.pdb file definatley exists in the working directory:

m1~/Temp/CHARMM_Tutorial/Scripts/>ls 4pti-a.pdb

It appears that charmm is not looking in my current working directory, because I can fix this error (and get the file to open) by modifying the following line:

open unit 21 read form name 4pti-a.pdb


open unit 21 read form name "$CHM_STREAM/H4pti-a.pdb"

CHARMM> open unit 21 read form name "$CHM_STREAM/4pti-a.pdb"
VOPEN> Attempting to open::/v/estor3/home/usr/Temp/CHARMM_Tutorial/Scripts/4pti-a.pdb::
OPNLGU> Unit 21 opened for READONLY access to /v/estor3/home/usr/Temp/CHARMM_Tutorial/Scripts/4pti-a.pdb

My question is, how do I get CHARMM to automatically look into my current working directory (from which I call charmm and run the scripts) to open files? I would like to avoid having to give the absolute path of the input files each time.