/*
Program: TEE.C
Author : Kim Moser
Date   : 4/14/89
System : IBM PC / Borland Turbo-C 2.0
Descrip: Copies stdin to both stdout and file specified.

Usage  : TEE <filename>
*/

#include <stdio.h>
#include <stdlib.h>
#include <io.h>
#include <fcntl.h>

void credits(void)
{
	fprintf( stderr, "TEE  v1.0 (4/13/89)  Copyright (c) Kim Moser  All Rights Reserved\n" );
}

void usage(void)
{
	credits();
	fprintf( stderr, "Copies stdin to stdout and to filename.\n" );
	fprintf( stderr, "Usage: TEE [-a] <filename>\n\n" );

	fprintf( stderr, "SWITCH  MEANING\n" );
	fprintf( stderr, "a       append to <filename>\n" );
	exit(1);
}

void main(argc, argv)
int argc;
char **argv;
{
	int ch;
	FILE *fp;
	char *fname=NULL;
	int append=0;
	int i,j;

	if (argc<=1 && argc>=4) usage();

	for (i=1; i<argc; i++)
		if (argv[i][0]=='-') {
			for (j=1; argv[i][j]; j++)
				switch(argv[i][j]) {
					case 'a':  /* Append */
						append=1;
						break;
					default:
						usage();
				}
		} else {  /* It's the filename */
			if (fname!=NULL)
				usage();
			else
				fname=argv[i];
		}

	if (fname==NULL) usage();

	if ( (fp=fopen(fname,append?"a":"w"))==NULL ) {
		fprintf( stderr, "Error opening file '%s' in mode '%s'.\n", fname,
		  append?"append":"write" );
		exit(1);
	}

	if (setmode(fileno(fp),O_BINARY)==-1) {
		fprintf( stderr, "Error setting mode of file '%s' to O_BINARY.\n", fname );
		exit(1);
	}

	while ((ch=getchar()) != EOF) {
		if (putchar(ch)==EOF) {
			fprintf( stderr, "Unable to put character to stdout.\n" );
			exit(1);
		}
		if ( fprintf(fp,"%c",ch) == EOF ) {
			fprintf( stderr, "Unable to put character to stderr.\n" );
			exit(1);
		}
	}

	if (fclose(fp)) {
		fprintf( stderr, "Error closing file '%s'.\n", fname );
		exit(1);
	}
}