compare two lists without grep?

[zarthan]

I have a small script that loops through a list of words in one file and compares them to a second list of words. If the words in list1 also exist in list2 output those words to list3.

for i in `cat ./list1` ; do
if grep -wq "$i" ./list2 ; then
echo "$i" >> ./list3
fi
done

The problem is I am stuck with busybox and this grep doesn't have -w so it does a partial match. I need some way to compare whole words only.

[Irithori]

This is actually a line by line compare, so not exactly what you are asking.

But if your busybox is compiled with comm,
you might try this:

comm -1 -2 file1 file2 > file3

BusyBox - The Swiss Army Knife of Embedded Linux

[Irithori]

sry, comm needs sorted lists.
So, busybox would have to include: sort, uniq, comm

sort file1 | uniq > tmp_file1
sort file2 | uniq > tmp_file2
comm -1 -2 tmp_file1 tmp_file2 > file3
rm tmp_file1 tmp_file2

[zarthan]

Don't have those either. I came up with this and it seems to work. I haven't tested every combination but . . .

Thanks

for i in `cat ./list1` ;do
awk -v var=$i -F, '$1==var' ./list2 >> ./list3
done