How can I find common words in two lists?

Since they're comma-separated, you could also import them into http://spreadsheets.google.com. At the end of each row, paste the formula =countif(A1:C2, "smith") Example: Adams | Jones | Smith | 2 Allen | Hughes | Smith | 1

Oops, sorry, I misread a key part of your question there, please disregard my advice. I still think an Excel/GSS formula might still be worth looking into, but the above would not yield the answer.

Supposing you have two files, 1.txt and 2.txt, containing one surname per line: cat 1.txt 2.txt | sort | uniq -d should do it.

this is ugly, but if you know that no name will be repeated in either list I'd do it something like this in Terminal.app perl -ne 'chomp; foreach $name (split(/, /)) {$seen{$name}++}; END {foreach $name (sort keys %seen) {print "$name\n" if $seen{$name} > 1}}' names1.txt names2.txt this splits on ", " counts the number of each name it sees, and then prints any that appear more than once. comm can also do the job if you can reformat the files to have 1 name per line instead of having them comma-seperated. In that case you probably want "comm -12 names1.txt names2.txt" to only print the matching items.

Thanks for the feedback, guys! Wayland: I tried your suggestion, but when I run (comm -1 -2 file1.txt file2.txt), nothing results. (comm -1 file1.txt file2.txt) shows me file 1's contents, (comm -2 file1.txt file2.txt) shows me file's 2's contents, (comm -3 file1.txt file2.txt) shows me both file 1 and file 2's contents. I can't seem to get the common terms for files 1 and two to show up! Christopherious, thanks for the info. Monday: I tried your suggest, and nothing happens when I run it. Pardon my lack of terminal knowledge. When I just run cat 1.txt 2.txt, I get the contents of both files. I must be doing something wrong.

Russm - didn't see your posting. Thanks, that code did work!

Do you mean each line is name(s) separated by commas or do you mean each list has one name per line? The second would be most common. The comm and a lot of other text tools require the files to be sorted in order to work. Your examples are if they are indeed one name per line. $ comm -1 -2 l1.txt l2.txt Smith But comm only works on 2 files. A more generic solution can be had many ways but the general idea is the same. Combine the files, sort them, count the number of duplicate lines and print those. $ sort l1.txt l2.txt | uniq -c | sort -n 1 Adams 1 Allen 1 Hughes 1 Jones 2 Smith This sorts the 2 lists together (could be any number of lists) and then counts the number of times each line is seen (then sorts the results of that numerically to make it easier to notice answers). Since 'Smith' is in both files it has a count of 2. You can take this a bit further like so: $ sort l1.txt l2.txt | uniq -c | awk '$1==2{print $2}' Smith Which just prints the second ($2, the name) column where the first column ($1, the count) is 2. You could do this with N files and match count of N (every file) or even $1>2 to list names that occur in more than 2 files. If your files really have each line like "Name1, Name3, Name3, ..., NameN" then I would split them up first because it's way easier to work with 1 name per line files. $ perl -lne 'print join("\n",split(/,\s+/))' list_N_per_line.txt > list_1_per_line.txt Will split up the lines in the file to one name per line. Oh, and don't feel bad about comm, it's a real PITA to use sometimes. # oblig Perl golf $ perl -lane '$c{$_}++;BEGIN{$c=@ARGV}END{do{print if$c{$_}==$c}for%c}' l1.txt l2.txt Smith

no worries... as others have said there are nicer ways of doing it if the data is newline separated rather than comma separated - that's generally The Unix Way(tm)...