AUSAM/source/S/emdoc

     How to Generate 'em'


     gfc 17

      Thu Apr 29 1976


                          How to Generate the QMC Unix Editor 'em'
                          ---------------------------------------


          Author:                 George Coulouris

                                Computer Systems Laboratory
               Queen Mary College  Mile End Road  London E1 4NS (01-980 4811 x751)



          Summary

               This is the system documentation for 'em'. It should  be  used
               in  conjunction  with  the  manual  section supplied with 'em'
               (EM(I), 3/22/76).  A  tutorial  introduction  to  'em'  is  in
               preparation.




          Files

               There are five relevant files:

                       emdoc           - the text of this document

                       em.n            - the text of the manual section
                                               on 'em' in 'nroff' format

                       emhelp          - a file containing a summary of
                                               editor commands, used in
                                               the 'help' command

                       em1.c           - the first of the two C  source  seg-
               ments

                       em2.c           - the second and last segment


          Generation

               To compile 'em':

                       cc -n -s em1.c em2.c

               leaves a suitable object program in 'a.out'. Just move  it  to
               '/bin/em':

                       mv a.out /bin/em

                                                                          1
     How to Generate 'em'


               to produce a command 'em'. If you also want a version with all
               of the 'em' features except prompting, you can make a link  to
               the  same  object  program with any name not having 'm' as its
               second character. We use the 'ed' name:

                       ln /bin/em /bin/ed

               If you want the editor to be  permanently  held  in  the  disc
               swapping  area (and therefore entered more quickly in response
               to the 'em' command) change the mode:

                       chmod 1755 /bin/em

          Frills

               If  you want the 'h' command to provide a screen full of help,
               put the text for the help in /usr/lib/emhelp. You can use  the
               file supplied, or make your own.

               There is a rather pleasing feature  available  when  you  type
               '^V' in the 'o' command that enables the spelling of a word to
               be given from a lexicon file once the first few letters of the
               word  have  been typed.  This is implemented through a command
               in our Unix system:

                       spell arg

               that takes an argument containing  an  alphabetic  string  and
               outputs  all  of  the  words in a lexicon file that begin with
               that string.  Our version of the spell program is a crude (but
               fast) affair using 26 files. There must be a better way, so if
               you want the '^V' facility we suggest you implement  your  own
               spell  command.  'em' will use it if it is there, otherwise it
               will display a suitable message.


                              ---------------/----------------



















                                                                          2