Argh. You're exactly right about the lsof -c option. My actual requirement is to search for files opened by a particular process - I somehow mungled this up while writing up my question. I suppose that's what I get for skipping my coffee this morning. :-) Good catch - and interesting info re: lsof's reporting of filenames. Also - that's a good point about the use of backticks. I'll switch to backticks for my other system calls and see how the numbers change.