Compare two text files line by line

Shell Programming and Scripting
1

Hi all

I need help on comparing two texts files line by line and print the total number of lines matched. Any help is appreciated. Thanks in advance.

2

"a" and "b" are the names of the files to compare.

IFS=''
exec 3<a 4<b
while true; do
    read -ru3 a && read -ru4 b || break
    [ "$a" == "$b" ] && echo
done | wc -l

Should work with bash and ksh (and probably most modern bourne variants).

Regards,
alister

3

I am getting an error message

read: 9: Illegal option -u

Anything is missing ?

4

Depends on what you actually mean by "line by line"...

$ head file[12]
==> file1 <==
a
c
d
e
f

==> file2 <==
a
b
d
f
g
$ comm -12 file1 file2 | wc -l
       3
$ paste -d '~' file1 file2 | awk -F '~' '$1==$2' | wc -l
       2

---------- Post updated at 02:46 PM ---------- Previous update was at 02:36 PM ----------

Using comm, there are 3 matching lines, i.e. lines containing "a", "d" and "f".
Using awk, there are 2 matching lines,i.e. line 1: "a" and line 3: "d". Note that the two lines containing "f" are not counted since they are on different lines.

5

Thanks a lot. I am using awk one. It works.