Shell Programming and Scripting

#!/usr/bin/ksh
 
#Program Name and Directory Name
PROG=`basename $0`
PROG_DIR=`dirname $0`
 
cd /home/test1   à There are two files in this directory BUILD1.dat and BUILD2.dat  with 200 and 6 records respectively.
 
if [ -f *.dat ] ; then
 echo "Input File found...."  
 
 inp_file=`ls -1 *.dat`
 echo "File Name: " $inp_file    
 
 line_cnt=`wc -l $inp_file | cut -c1-8`
 echo "The line count is: $line_cnt"   à  This returns three values 200  and 6 and 206.
 
diff= `expr 301 - $line_cnt`
echo "The change is: $diff"    à This is my issue. I am not getting any values to this....
 
actual_diff=`expr $line_cnt - 1`  
echo "The actual count is: $actual_diff"      à This is my issue. I am not getting any values to this....
else
 echo "File Not found"
fi

[house@leonov] wc -l in.file
9 in.file
[house@leonov] lines=$( wc -l in.file | cut -d ' '  -f 1 ); diff=$( expr $lines - 1 ); echo "$diff"
8