Multiple file input

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# 1  
Old 01-15-2014
Multiple file input

Once a time, I did see a way to multiply a file input in bash, but have forgotten how it was done.

awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' file file

Here you need file two times.
I seen it some like this
awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' 2&file

# 2  
Old 01-15-2014
You seem to have already answered your question, what would you like from us? That is awk, not bash, by the way.
# 3  
Old 01-15-2014
researched something similar

I was just looking into this. What I've found is the following:

awk 'NR==FNR{a[$1];next}$1 in a{print $1}' F1 F2

NR==FNR -- this will only be true when in the first file
a[$1] use the first column to make array of file
next skip all the next blocks and process the next line
($1 in a) check in value in column on of second file
then print it

gawk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}'

So this is NR==FNR same as above
a[$1] s same as above
$2 in a -- is column $2 in the array of second file? then print it
# 4  
Old 01-15-2014
This does not work, it gives me:
awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' 2&file
[1] 7183
awk: cmd. line:1: fatal: cannot open file `2' for reading (No such file or directory)
t: command not found
[1]+  Exit 2                  awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' 2

2&file would be some like this. Run awk with file name 2, and if ok, the run command file
I would like to substitute file file with some that returns file two or more in on go.

My awk does compare first and second column, and if equal print what is equal.
It does not care what row its in, just compare every number anywhere in the column.

Last edited by Jotne; 01-15-2014 at 02:20 PM..
# 5  
Old 01-15-2014
-- deleted--
# 6  
Old 01-15-2014
Originally Posted by Jotne
This does not work, it gives me:
[CODE]awk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}' 2&file
[1] 7183
awk: cmd. line:1: fatal: cannot open file `2' for reading (No such file or directory)
Well, it means what it says... There's no file named '2'. If you want to give it some other, more valid filename, you are free to do so.

It takes the & to mean 'run this command in background and take the text after as a new command'.

I would like to substitute file file with some that returns file two or more in on go.
I do not understand this. If you want awk to read the file twice, you tell it the file twice; that's how it works. But I don't think your question is crossing the language barrier very well.
# 7  
Old 01-15-2014
Post files

Do you have a couple files with output? Files before you run the command, and what you expect after?

Also, I've noticed that on my system a lot of what runs for others with awk only works with gawk for me. Have you tried gawk?
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