i have a file which has the following lines:

1GEG
3RU7
1BXS
2JG7
3QWU
2BHP
3ABU
[download]

I also have another file as:

a.1.1.1 1GEG
a.4.3.5 1BXS
a.6.7.5 2JG7
a.8.7.9 2BHP
a.3.2.1 3RU7
[download]

I need to do the following task : for each value in file1, i have to check whether that value exists in second field of file2, and if it does, i want to extract out the corresponding "FIRST FIELD" of file2. In short I want smthing like this:

1GEG => a.1.1.1
3RU7 => a.3.2.1
1BXS => a.4.3.5
2JG7 => a.6.7.5
3QWU => NIL
2BHP => a.8.7.9
3ABU=> NIL
[download]

i have the logic. i know this will work. bt i am not able to get it into proper code. here it is: read the elements of first file into a hash, and then if the hash key exists for a line I read from the second file, then it obviously existed in the first file. how do i go about it?

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