# cat file1
line1 a b c
line3 c d e
line2 q l r
# cat file2
line1 a b c
line2 q l r
line3 c d e
# cat file3
line3 c d e
line2  l r
line1 a b c

# diff file1 file2
2d1
< line3 c d e
3a3
> line3 c d e
 
echo $? # output return code
1

#sort file1 > file1.sort
#sort file2 >file2.sort
#diff file1.sort file2.sort
#echo $?
0

#!/bin/ksh
sort ${1} > /tmp/${1}.sort
sort ${2} > /tmp/${2}.sort
 
diff /tmp/${1}.sort /tmp/${2}.sort >/dev/null 2>&1
if [ $? -eq 0 ] 
then echo "files are equal"  ; RC=0
else echo "files are not equal" ; RC=1
fi
 
rm /tmp/${1}.sort
rm /tmp/${2}.sort 
 
exit $RC

# ./compare.ksh file1 file3
files are not equal
# ./compare.ksh file2 file1
files are equal