Shell Programming and Scripting

file1:
one
two
three

file2:
two
four
six

file3:
one
two
ten

These are all in a directory called dir1

x_file1:
one
six
ten

x_file2:
three
eight
nine

x_file3:
seven
one
five

These are all in a directory called dir2

output:
two
four

cd dir1
awk ' {arr[$0]++; next} END {for(i in arr){print i}} ' file* > /tmp/summed.txt

cd another_dir
awk ' NR==FNR {arr[$0]++; next} {arr[$[0]++; next} 
         END{for(i in arr){if(arr[i]>1{print i}}}'  /tmp/summed.txt X_file* > output.txt

awk '
d==0 {  a1[$0]
        next
}
{       a2[$0]
}
END {   for(i in a1)
                if(!(i in a2))
                        print i
}' dir1/* d=2 dir2/*

./junk: line 4: cd: dir2: No such file or directory
awk:  NR==FNR {arr[$0]++; next} {arr[$[0]++; next}
awk:                                  ^ syntax error
awk: fatal: invalid subscript expression