COMPILING

rc was written in portable ANSI C.  If you don't have an ANSI compiler
like gcc or something close (e.g., sgi's cc) read further down on
how to convert rc's source to old C.

rc uses GNU autoconf and automake.  The following commands are all you
need to configure, build, test, and install rc.

    $ sh configure
    $ make
    $ make trip
    # make install

This will build rc in the source directory.  You can also run these
commands from any other directory, specifying the path to the configure
script, and rc will be built in that directory.  This is particularly
useful if you are building rc for multiple architectures.

There are lots of options you can give to configure to modify rc's
behaviour.  You can also select a command line history library to link
against.  For a summary of all options, run `sh configure --help'.

You can specify Makefile variables by setting the corresponding
environment variables.  For example, you might want to set `CC=cc', to
prevent configure looking for gcc, or set an initial value for `LIBS',
as in the example below.

Here are the configure options you may want to use, in approximately
descending order of usefulness.

  --with-editline

  This option tells rc to use Simmule Turner's and Rich $alz's editline
  package, which you can get from the following location.  This is
  essentially a lightweight version of GNU readline, providing EMACS
  style command line editing and history.

    ftp://ftp.cygnus.co.uk/people/tgoodwin/editline.tar.gz

  If the editline library is not installed in a standard place, you can
  tell configure where to find it by setting the environment variable
  LIBS.  For example, the maintainer builds rc by copying libedit.a into
  the rc build directory and then running this configure command.

    LIBS=-L. sh ../rc-1.5b3/configure --with-editline

  --with-readline

  This option tells rc to use the GNU readline package, which is similar
  to editline, but has many more features.  The readline package is
  over 6 times the size of editline (whether you count lines of code,
  or the library itself).  As for editline, you can set the environment
  variable LIBS if your readline library is not installed in a standard
  place.

  --enable-history

  Use this option if you want to build and install the programs that
  support a crude history mechanism.

You can't use `--with-editline' and `--with-readline' together, of course,
and if you have either of those you probably don't want to bother with
`--enable-history'.

  --prefix=/path

  By default, `prefix' is /usr/local, which means that `make install'
  installs rc (and possibly the history programs) in /usr/local/bin, and
  man pages in /usr/local/man/man1.  Use this option to change where
  `make install' puts things.

  --disable-builtin-echo

  By default, the `echo' command is builtin to rc for efficiency reasons.
  It is the only builtin which is not essential, and purists may wish
  to omit it.

  --disable-def-interp
  --enable-def-interp=/bin/foo

  By default, a program that fails with "Exec format error" is handed to
  /bin/sh.  This does the Right Thing for scripts that start with `:' to
  indicate that they are sh scripts.  You can disable this behaviour
  entirely, or specify a different default interpreter.

  --disable-def-path
  --enable-def-path="/usr/local/bin","/usr/bin"

  By default, if rc is started with no PATH, it uses a default path.
  The default path is constructed at configure time, and consists
  of each of the following directories that exist, in order.

      /usr/local/bin /usr/bin /usr/ucb /bin .

  You can disable this, or specify a different default path.  Note
  that the quote marks (") must be seen by configure; you will
  probably need to quote them to your shell.  (Not if it's already
  rc, but then you will need to quote the `='.)

  --disable-job

  By default, rc puts backgrounded processes into a new process group,
  as though it were a job control shell (it isn't).  This is usually
  needed to work around bugs in application programs which install
  signal handlers for the keyboard signals without checking whether the
  signal was being ignored.  This option disables the default behaviour,
  making rc behave like a traditional sh.  You are unlikely to want this
  option on any Unix system.

  --disable-protect-env

  By default, rc encodes special characters in environment variables.
  This is necessary on all known Unix systems to prevent sh either
  dying or discarding the variables.  This option disables the default
  behaviour.  You are unlikely to want this option on any Unix system.

After you've built rc, you may wish to run it through a test script
to see that everything is ok.  Type `make trip' for this.  This will
produce some output, and end with "trip is complete".  If the trip ends
with "trip took a wrong turn..." please contact the maintainer.

YACC

The yacc that Sun ships with SunOS 4.1.1 calls malloc() to allocate
space for the state stack, and requires a call to YYACCEPT or YYABORT to
free this memory.  This means that if rc takes an interrupt while parsing
a command (say, if ^C is typed), yacc will leak away this memory.  The
solution is to use a yacc which statically allocates this array, such
as the yacc in the BSD distribution.  Berkeley yacc-generated y.tab.c
and y.tab.h are shipped with rc in case you cannot get hold of Berkeley
yacc.

OLD C

If you need to convert rc's source into K&R C, you need to run the
source through a filter called "unproto", posted in comp.sources.misc.
A sample "cpp" shell script that I used to run unproto under SunOS is
supplied with rc.