Shell Programming and Scripting

(sh shell) I have a function I am using that does a date calculation so I can subtract dates.

Code:

get_JD () {
bc << MSG
scale=0
date calculation  ……….......
MSG
}

Then I have this little script that runs after it.

Code:

read XXX < TESTFILE
pastdate=`get_JD $XXX`
currdate=`get_JD &YYY`
diff=`expr $currdate - $pastdate`
echo $diff

The only problem is that it only reads the first line in my file named TESTFILE. Is there a way to write a while loop so that it can keep working until it reaches the end of this file? Or is there a better way to do this?

use a while loop to read a file

Code:

while read XXX 
do
  pastdate=`get_JD $XXX`
  currdate=`get_JD &YYY`
  diff=`expr $currdate - $pastdate`
  echo $diff
done  < TESTFILE

Thanks Jim! Works great.