Calc command line

    Calc has the following command line:

	calc [-h] [-m mode] [-p] [-q] [-u] [calc_command ...]

	-h  Print a help message.  This option implies  -q.  This
	    is equivalent to the calc command help help.  The help
	    facility is disabled unless the mode is 5 or 7.  See -m.

	-m mode
	   This flag sets the permission mode of calc.  It
	   controls the ability for calc to open files and execute
	   programs. Mode may be a number from 0 to 7.

	   The mode value is interpreted in a way similar to that
	   of the chmod(1) octal mode:

		0  do not open any file, do not execute progs
		1  do not open any file
		2  do not open files for reading, do not execute progs
		3  do not open files for reading
		4  do not open files for writing, do not execute progs
		5  do not open files for writing
		6  do not execute any program
		7  allow everything (default mode)

	   If one wished to run calc from a privledged user, one
	   might want to use -m 0 in an effort to make calc more
	   secure.

	   Mode bits for reading and writing apply only on an
	   open.  Files already open are not effected. Thus if one
	   wanted to use the -m 0 in an effort to make calc more
	   secure, but still wanted to read and write a specific
	   file, one might want to do:

		     calc -m 0 3<a.file

	   Files presented to calc in this way are opened in an
	   unknown mode. Calc will attempt to read or write them
	   if directed.

	   If the mode disables opening of files for reading, then
	   the startup library scripts are disabled as of -q was
	   given.  The reading of key bindings is also disabled
	   when the mode disables opening of files for reading.

	-p  Pipe processing is enabled by use of -p.  For example:

		     echo "print 2^21701-1, 2^23209-1" | calc -p | fizzbin

	    In pipe mode, calc does not prompt, does not print
	    leading tabs and does not print the initial header.

	-q  Disable the use of the $CALCRC startup scripts.

	-u  Disable buffering of stdin and stdout.

    Without calc_cmds, calc operates interactively.  If one or more
    calc_cmds are given on the command line, calc will execute them and
    exit.  The printing of leading tabs on output is disabled as if
    config("tab",0) had been executed.

    Normally on startup, calc attempts to execute a collection of
    library scripts.  The environment variable $CALCRC (if non-existent
    then a compiled in value) contains a :  separated list of startup
    library scripts.  No error conditions are produced if these startup
    library scripts are not found.

    If the mode disables opening of files for reading, then the startup
    library scripts are disabled as of -q was given and $CALCRC as well
    as the default compiled in value are ignored.

    Filenames are subject to ``~'' expansion (see below).  The
    environment variable $CALCPATH (if non-existent then a compiled in
    value) contains a : separated list of search directories.  If a
    file does not begin with /, ~ or ./, then it is searched for under
    each directory listed in the $CALCPATH.  It is an error if no such
    readable file is found.

    Calc treats all open files, other than stdin, stdout and
    stderr as files available for reading and writing. One may
    present calc with an already open file in the following way:

        calc 3<open_file 4<open_file2

    For more information use the following calc commands:

       help usage
       help help
       help environment