The section named ``Return Values'' on page 56 introduces the <> operator for obtaining the return value of a command. That operator has been renamed <= to avoid conflicting with the posix-compatible defintion of <> as ``open for reading and writing.'' error exceptions now have an additional piece of information. the second word (the one after ``error'') is now the name of the routine which caused the error. Thus, in the example below, the throw command has an extra ``in'' in it. The example at the top of the right-hand column on the fourth page (page 56 in the Usenix proceedings) uses an obsolete version of the fork builtin. The in function should now be fn in dir cmd { if {~ $#dir 0} { throw error in 'usage: in dir cmd' } fork { # run in a subshell cd $dir $cmd } } The pipe timing example from the paper may not work on your system. It depends on having a version of time(1) that understands es, either by building it in to es or having an external time use the SHELL environment variable. Es will include a (minimal) time function if it is built with BUITIN_TIME.