join ?

[Maarten . Vanneste]

Hello,

I have the following question about the join command. I thought join would 
merge the columns of different files when the same index or value is 
present in the specified columns. Now I have the impression that it does 
not work fine when the two data files do not have the same number of 
values or range.

For example, I created the following files:
echo 84 150 | gawk '{for (i=$1;i<=$2;i++) printf "%i %s\n", i,"A"}' > 
testA
echo 109 150 | gawk '{for (i=$1;i<=$2;i++) printf "%i %s\n", i,"B"}' > 
testB
join -1 1 -2 1 testA testB > testAB
This file is empy, though I anticipated the rows from values 109 to 150 to 
be joined.

Using 84 (or 109) instead of 109 (or 84) gives the expected output. I 
thought the join command would read one file and scan the other to find 
the corresponding record, and as such only return those rows occurring in 
the two files.

I tried this on both cygwin (6.10) and linux operating system (6.9).

Looking forward to hearing from you,
Maarten


=================
Dr. Maarten Vanneste
International Centre for Geohazards - Norwegian Geotechical Institute
Oslo, Norway
www.geohazards.no
www.ngi.no

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