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Comparing two files by two matching fields


 
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# 1  
Old 01-24-2019
Comparing two files by two matching fields

Long time listener first time poster. Hope someone can advise.

I have two files, 1000+ lines in each, two fields in each file.

After performing a sort, what is the best way to find exact matches where field $1 and $2 in file1 are also present in file2 on the same line, then output only those into file3?

Field 1 will always be unique within the files, but not field 2, there could be numerous entries of the same text.

So where field 1 and field 2 on a line in file 1, both only exist on the same line in file 2, output to file 3.

Thanks in advance.

File 1
Code:
abcdefgh    name1
bcdefgha    name2
nmrsthji    namei
nmdherya    wood
kasjfhsw    moon
pqoweiru    sun
wershgsy    other
iundhstw    tree            
gfhskwyt    mine
alskalak    hoover

File 2
Code:
abcdefgh    name1
bcdefgha    name5
hjgdrnja    namej
nmdherya    notwood
kasjfhsw    moon
wershgsy    other
pqoweiru    sun
        
 gfhskwyt    mine
alskalak    hoover

--- Post updated at 02:25 PM ---

Confusing myself.

I dont mean field 1 and field 2 on line 3 in file 1, have to be on line 3 in file 2.
But field 1 and 2 on line 3, must match in file 2, on any line, then output to file 3.

Smilie




Moderator's Comments:
Mod Comment Please use CODE tags as required by forum rules!

Last edited by RudiC; 01-24-2019 at 11:28 AM.. Reason: Added CODE tags.
# 2  
Old 01-24-2019
Welcome with your first post.


Being a long time listener, you might be aware that the preferred approach in here is to show your own efforts, like code attempts, or thoughts on a solution. The posted problem has been addressed umpteen times in these fora, and you might find a good starting point searching, e.g. the links given in the lower left of this screen, under "More UNIX and Linux Forum Topics You Might Find Helpful".
On top, a desired output would clarify the situation.
# 3  
Old 01-24-2019
Thanks for the reply, will keep searching.

Output into file three, in the form of either field 1 and field 2 that match in both files.
Or field 1 and field 2 that match in both, if it duplicates output, can live with that.
# 4  
Old 01-24-2019
Quote:
Originally Posted by bstaff
Thanks for the reply, will keep searching.

Output into file three, in the form of either field 1 and field 2 that match in both files.
Or field 1 and field 2 that match in both, if it duplicates output, can live with that.
Hi bstaff,
I think we already understand the you want the results to be stored into a third file (rather than just letting the output be sent to the program's standard output so you could redirect it wherever you wanted it to go). The question is: "Given the contents of File 1 and File 2 that you showed us in post #1 in this thread, exactly what output do you hope will be stored in your output file?

Note also that the description of your problem talks about file 1 and file 2 (with entirely lowercase "file" in both cases), but when you showed us sample contents for those files you showed labels with initial caps on both filenames. On most BSD, Linux, and UNIX filesystems, case matters in filenames.
# 5  
Old 01-24-2019
File 3 full of matches.

Field 1 and Field 2 on a same line in File 1 are also present in File 2 on a same line.
Code:
abcdefgh name1
kasjfhsw moon
pqoweiru sun
wershgsy other        
gfhskwyt mine
alskalak hoover

Does that explain it? Smilie

Last edited by Don Cragun; 01-24-2019 at 05:46 PM..
# 6  
Old 01-24-2019
I'm not sure why your search in here has not yet been successful, as many of the links show promising starting points, and with some - not too much - fiddling your problem can be solved:
Code:
awk 'NR == FNR {T[$1,$2]; next} ($1,$2) in T' file[12]
abcdefgh    name1
kasjfhsw    moon
wershgsy    other
pqoweiru    sun
gfhskwyt    mine
alskalak    hoover

Redirect to file3 if happy with what you see.
This User Gave Thanks to RudiC For This Post:
# 7  
Old 01-25-2019
Perfect, thank you for your time and effort, works great.

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