$ 
$ # display the file "num" that has floating-point numbers, one per line
$                                                                    
$ cat num                                                            
2.1                                                                  
3.4                                                                  
4.6                                                                  
5.2                                                                  
6.3                                                                  
$
$ # display the script
$
$ cat test_scr.sh
#!/bin/bash
NUMFILE=$1
total=0
if [ -c $NUMFILE ]
then
  echo "Our input is from a Device"
  while read LINE; do
    total= `echo $total + $LINE | bc`
  done < $NUMFILE
elif [ -p $NUMFILE ]
then
  echo "Our input is from a pipe"
  while read LINE; do
    total= `echo $total + $LINE | bc`
  done < $NUMFILE
elif [ -f $NUMFILE ]
then
  echo "Our input is from a file"
  while read LINE; do
    total=`echo $total + $LINE | bc`
  done < $NUMFILE
fi
echo total is $total
$
$ # test the script, passing "num" as input
$
$ . test_scr.sh num
Our input is from a file
total is 21.6
$
$