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Check your log file for
systems : system commands are enabled
Thanks, that was the problem. It was saying 'disabled' instead. The fix was to change /etc/texmf/texmf.cnf to enable write18. The shell_escape line has to be set to 't' rather than 'f', i.e.: shell_escape = t Actually, on my system (Ubuntu, a Debian derivative), changing the texmf.cnf file directly is not a good idea. Instead one should change the same line in /etc/texmf/texmf.d/95NonPath.cnf and then run 'update-texmf' as root to generate the texmf.cnf file. Warning: If you've enabled 'shell_escape', then don't run *TeX on untrusted files, in case they do anything malicious like 'rm -fr /'. Also now I see how I got fooled into thinking that write18 was already enabled. The one-line tex file from metafun-s.pdf contains \immediate\write18{echo It works}. When run it produces an "It works" whether or not write18 is enabled. If disabled: (./3.tex echo It works ) which made me think that all was okay. If enabled you get this: \write18 enabled. (./3.texIt works ) -Sanjoy `Never underestimate the evil of which men of power are capable.' --Bertrand Russell, _War Crimes in Vietnam_, chapter 1.