CS 120 / Lab 2 - Feb 4 and 5, 2010
Allison Mankin, amankin1@jhu.edu

1. use 'ps' to observe that your shell is 'tcsh' (Tom's csh)

2. edit ~/.tcshrc to define persistent aliases such as:
     alias rm      'rm -i'
     alias gcc120   'gcc -ansi -std=c99 -pedantic -Wall -Wextra -O'
   start them temporarily by typing 'source ~/.tcshrc' 
   they will be set up every login after this

3. review emacs usage and add some new capabilities
   ctl-x-ctl-f     find or create file
   ctl-x ctl-s     save file
   ctl-z           background emacs, go to command line
 
   ctl-z puts any program, not just emacs, in the background
   type 'fg' (foreground) to return to a ctrl-z'd program
   if multiple are running, type 'jobs' and then 'fg %<number'
   kill -9 %<number> to end backgrounded programs
 
   new emacs capabilities:
   ctl-x-2         split screen in 2
   ctl-x-1         return to 1 screen (the one cursor is in now)
   ctl-x-o         move cursor to other screen
   ctl-x-0         close (zero) the screen you're in (but not the file) -
                   your focus moves to the other (or previous) screen

   ctl-x-ctl-b     display buffer list in other window - then use ctl-x-o
                   to enter that screen.  Buffers are files you are editing
                   or emacs outputs.  When in the buffer list, type an 'f'
                   next to listed file or item and that item will be come to
                   the screen.

  esc-x-compile    in emacs many commands have keystroke bindings but sometimes
                   they have names.  A named command like this is entered by
                   typing the ESC key then 'x' then the name, in this case, the
                   word 'compile'

4. simple regular expressions (very basic, useful)
      * (any number of any character, anywhere), c*, *.c, c*.c

     [A-Z]*, [a-z]*, [0-9], [Ab3]*.c (everything beginning with A, b or 3),

     [A-Z][0-9]* (everything beginning with a capital letter followed by a number), etc.


5. exercise:
   cd to /usr/bin
   use simple regular expressions, pipes (|) and wc to count the number of 
   programs in /usr/bin that contain the string 'config' and the number that
   contain the string 'check'

   e.g. ls *config* | wc -l


6. compilation with emacs and a simple makefile
   use 'wget' to bring wpa.c to your ugrad home directory
   emacs wpa.c.
   ctl-x ctl-f Makefile (create the file named 'Makefile') and
   edit the following super simple makefile for gpa.c

     CFLAGS= -ansi -pedantic -Wall -Wextra -std=c99 -O
     CC=gcc

     gpa: gpa.c

 Be sure to save Makefile (ctl-x, ctl-s)
 Use esc-x-compile and review the compiler output in the emacs window

6. If time permits, use the emacs compiler function by introducing a
   c error in gpa.c and editing gpa.c, and recompiling.  Just save gpa.c each
   time you edit, before you type esc-x-compile again.

7. Back on the command line, type 'cp wpa.c wpa-copy.c' then back in
   emacs bring wpa-copy.c into emacs.  If time permits, edit a c error into
   gpa-copy.c and save it  Add the following line to Makefile and save it.

     gpa-copy: gpa-copy.c

   When you type esc-x-compile, tell emacs to 'make -k gpa-copy'
   Look with the compile output for the code with an error.  Don't correct
   it.  Exit emacs.

8. On the command line, type 'diff wpa.c wpacopy.c > wpadiffs'
   Type 'cat wpadiffs' and explain what the output means


--------------------
Mini-refresher of emacs commands

ctrl-p  cursor up
ctrl-n  cursor down
ctrl-f  cursor forw
ctrl-b  cursor back
ctrl-e  cursor to end of line
ctrl-a  cursor to start of line
ctrl-[  cursor to start of flie
ctrl-]  cursor to end of file

ctrl-k cut
ctrl-y paste
ctrl-o open line above