A few spy tools for your operating system (other than strace)
That's indeed a useful list. lsof alone covers a lot of ground!Mac OS X has a pretty nice set of DTrace scripts built in: http://dtrace.org/blogs/brendan/2011/10/10/top-10-dtrace-scr...The ones I use the most:* iosnoop: see all disk I/O. especially useful to find disk-chatty/poll-y apps.* execsnoop: see new processes being spawned.* opensnoop: see file opens. especially useful for failed file opens that break an app.* dtruss: see all system calls. get access to the entire OS interaction history of an process (or app).* errinfo: trace failing system calls. where there is smoke...* iotop -- who is using diskThere is just a crazy, crazy list of things available, built-in:  man -k dtrace

Edit: wow HN formatting sucks so bad. I wish I could make that list more readable, but apparently I can't.