Unix one liner: Combine 2 headed files

Question

If I have 2 files where the first lines contain identical headings:

A.txt:

A 1 aa

B.txt

A ee 7

I want to combine them like so:

C.txt

A 1 aa ee 7

Is there a one liner to do this?

Do you want this to happen only if the header is the same? — mattdm
– mattdm, Commented Dec 3, 2010 at 13:05
Not necessary.. I'm thinking of a simple case when I know the headers are the same. Handling the case where the headers can be slightly different might be the subject of another question :-) — StamfordBingo
– StamfordBingo, Commented Dec 3, 2010 at 13:27

Ignacio Vazquez-Abrams · Accepted Answer · 2010-12-03 11:42:24Z

3

tail -n +2 B.txt | cat A.txt - > C.txt

answered Dec 3, 2010 at 11:42

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shaktale · Accepted Answer · 2010-12-03 13:01:37Z

0

If order is not a problem:

sort A.txt B.txt | uniq

answered Dec 3, 2010 at 13:01

1

Dennis Williamson · Accepted Answer · 2010-12-03 16:56:36Z

Here's another way that's easily scalable to any number of input files (just add them as additional arguments:

awk 'FNR!=NR&&FNR==1{next}{print}' A.txt B.txt > C.txt

3 Answers 3