Compare two text files and print matches

Shell Programming and Scripting
1

Hi,

I am looking for a way to compare two text files and print the matches. For example;

File1.txt

89473036
78474384 
48948408
95754748
47849030

File2.txt

47849030 
46730356
16734947
78474384 
36340047

Output:

78474384
47849030
2 
awk '{++a[$2]} END {for(i in a) if(a>1) print i}' file1 file2
3 
awk 'NR==FNR{a[$2];next}$2 in a{print $2}' file1 file2

--ahamed

4

Hi guys,

Thanks for the help so far, however both statements print blank lines and I think it is because I need to tweak my example.

To elaborate further, it only contains numbers but the numbers are not a fixed length as in my first example.

File1.txt

8947303689037809238094
7847438449838
4894840834098337
95754748280926266290
478490309034879362612

File2.txt

47849030292119167904387
46730356340247247474934994287
478490309034879362612 
4894840834098337 
363400472727249727

Output:

4894840834098337
478490309034879362612
5

Do you have the serial # at the beginning of the file? i.e. 1. 2. etc
And which is your OS? If solaris, use nawk

If you fon't have serial no, then use this...

grep -f file2 file1

--ahamed

6

There is no structure to the data really, each line is unique. I need a formula to cat file 1, cat file 2 and print the matching lines.

I am on Linux, grep -f printing blank.

7

Have you tried ahamed's suggestions? They should work if your input file is anything like you described. What do you mean with no structure? What you have posted so far is two files with 2 fields per line. The first field is a serial number followed by a dot, the second is a number of arbitrary length. Is this correct or does the structure deviate from this?

8

Ahh man, my apologies those were meant to be line numbers, they were not necessary. My text editor notes the line numbers and I added them to my original post without realising Ahamed's suggestion took it into consideration. My bad, I have now removed them. :wall:

9 
awk 'NR==FNR{a[$1];next}$1 in a{print}' file1 file2

or

grep -f file1 file2

When I copied your contents, there were spaces at the end of some lines (and that is probably the reason why grep didn't work), if that is the case use awk else the grep should do the job!

--ahamed

10

And if there are no double entries in the first file then this should work too:

awk 'A[$1]++' file1 file2
11

Thanks guys, the awk statements are working well now!

12

Can any one give me the whole programming for this need in perl?? please