This is a version of tty.c for linux.

john harvey    JOHNBOB at AUSVMQ    I don't speak for my employer.
johnbob@innerdoor.austin.ibm.com    johnbob@there.austin.ibm.com
johnbob@129.35.81.111               johnbob@129.35.81.200
  main(int c,char**v){if(c==2){int n=atoi(v[1]);printf("%d\n",
  n*main(-n+1,v));}else if(c<0)return-c*main(c+1,v);return 1;}

---- Cut Here and unpack ----
#!/bin/sh
# This is a shell archive (shar 3.10)
# made 01/21/1992 18:47 UTC by rjohnbobpts/4@AIX
# Source directory /drive2/u/johnbob/net/linux/contrib
#
# existing files will NOT be overwritten
#
# This shar contains:
# length  mode       name
# ------ ---------- ------------------------------------------
#    170 -rw-r--r-- Makefile
#    158 -rw-r--r-- add.this
#    587 -rw-r--r-- tty.c
#
touch 2>&1 | fgrep '[-amc]' > /tmp/s3_touch$$
if [ -s /tmp/s3_touch$$ ]
then
	TOUCH=can
else
	TOUCH=cannot
fi
rm -f /tmp/s3_touch$$
# ============= Makefile ==============
if test -f Makefile; then echo "File Makefile exists"; else
echo "x - extracting Makefile (Text)"
sed 's/^X//' << 'SHAR_EOF' > Makefile &&
X#
X#
X
XPROGRAM = tty
XSRC	= tty.c
XOBJS	= tty.o
X
XCC=cc
XCFLAGS	= -O
X
X
Xall: $(PROGRAM)
X
X$(PROGRAM): $(OBJS)
X	$(CC) -o $(PROGRAM) $(OBJS) $(LIBS)
X
X.c.o:
X	$(CC) $(CFLAGS) -c $<
X
SHAR_EOF
chmod 0644 Makefile || echo "restore of Makefile fails"
if [ $TOUCH = can ]
then
    touch -am 0120162992 Makefile
fi
fi
# ============= add.this ==============
if test -f add.this; then echo "File add.this exists"; else
echo "x - extracting add.this (Text)"
sed 's/^X//' << 'SHAR_EOF' > add.this &&
XThe prototype for the ttyname() function wasn't in
X/usr/include/unistd.h so you will have to add it to
Xthe bottom of the file:
X
Xchar * ttyname(int fildes);
X
X
SHAR_EOF
chmod 0644 add.this || echo "restore of add.this fails"
if [ $TOUCH = can ]
then
    touch -am 0120174392 add.this
fi
fi
# ============= tty.c ==============
if test -f tty.c; then echo "File tty.c exists"; else
echo "x - extracting tty.c (Text)"
sed 's/^X//' << 'SHAR_EOF' > tty.c &&
X/*
X    tty.c
X    By John Harvey AKA johnbob AKA qk
X    copy this all you want
X*/
X
X#include <sys/types.h>
X#include <stdio.h>
X#include <unistd.h>
X
Xvoid syntax(int rv)
X{
X    fprintf(stderr,"syntax: tty [-s]\n");
X    exit(rv);
X}
X
Xmain(int argc, char **argv)
X{
X    int silent = 0;
X    char *n;
X
X    if( argc == 2 )
X    {
X	if( strcmp(argv[1],"-s") )
X	    syntax(1);
X	silent = 1;
X    }
X    else if ( argc != 1 )
X	syntax(1);
X    if( n=ttyname(0) )
X    {
X	if ( ! silent )
X	    printf("%s\n", n);
X	exit(0);
X    }
X    else
X    {
X	if ( ! silent )
X	    printf("%s\n", "Not a tty");
X	exit(1);
X    }
X}
SHAR_EOF
chmod 0644 tty.c || echo "restore of tty.c fails"
if [ $TOUCH = can ]
then
    touch -am 0120173492 tty.c
fi
fi
exit 0