jik@athena.mit.edu (Jonathan I. Kamens) (11/09/90)
(Note the Followup-To, which probably should have been set to something in the original posting. I was all set to flame at the poster for posting a question to comp.unix.internals that doesn't have anything at all to do with Unix internals, and then I realized that he posted it to comp.unix.wizards, which is aliased to comp.unix.internals, at least at my site. :-) In article <1990Nov8.014515.13882@cpsc.ucalgary.ca>, paquette@cs-sun-fsa.cpsc.ucalgary.ca (Trevor Paquette) writes: |> alias host '`echo set path=\($path\)|sed s/itaqc/itahost/|sed s/itasc/itahost/`' |> alias qc '`echo set path=\($path\)|sed s/itahost/itaqc/|sed s/itasc/itaqc/ `' |> alias sc '`echo set path=\($path\)|sed s/itaqc/itasc/ |sed s/itahost/itasc/`' |> But these new aliases give me the following error: |> |> `echo set path=\($path\)|sed s/itaqc/itahost/|sed s/itasc/itahost/`: Ambiguous The C-shell has a problem (discussed several times in comp.unix.shell recently) with deciding exactly when the output of a backquote substitution should be expanded into multiple words. Another example of this is that typing kill `cat file-with-list-of-pids-in-it` won't work because the list of pids will all be treated as one word. This is only a problem with the "kill" shell built-in, though, so if you substitute "/bin/kill" for "kill", it works fine. The problem you are having is another manifestation of this. The way to get around it is to change your aliases. For example; alias host 'set path= (`echo $path|sed -e s/itaqc/itahost/g -e \\\ s/itasc/itahost/g`)' Note that this has the added advantages of using only one invocation of sed instead of two, and of replacing itasc and itaqc whereever they appear in your path, not just the first time. You could also solve the problem by using eval instead of backquotes, although you might have to make some minor changes to your aliases in that case too. Figuring out how to do this is left as an exercise to the reader :-). -- Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8085 Home: 617-782-0710