i have try , but i think i will never learn awk
now i have 2 files :

a
1:aaa:2:aaa1
2:bbb:2:bbb1
3:ccc:3:ccc1

b
aaa:2
bbb:0
ccc:3

output:
for all lines where a.$2 == b.$1
i want to compare a.$3 != b.$2 if true then set err=1 if false set err=0
and print all lines from file a + err

Thanks & regards
Peter

what other languages do you know..? there's no restriction for you if you don't like awk. you can do what you want in most other languages. The standard algo is the same.
1) open file1
2) read a line
3) split the components and get the ones you need to compare
4) open file2
5) read the line
6) split the components and get the ones you need to compare to 3)
7) compare
8) display results
9) close the files

Hi,
I think this one should be ok for you! Please try.

paste file1 file2 | sed 's/ /:/' > temp
awk 'BEGIN{OFS=FS=":"}
{
if($2==$5)
if($3==$6)
print $1":"$2":"$3":"$4":"0
else
print $1":"$2":"$3":"$4":"1
}' temp