Shell Programming and Scripting

I have two files

(___ represents blanks)

Foo1

1000 345 456
1001 876 908
1002 ___ 786
1003 643 908
1004 345 234

and Foo2

1000 345
1001 876
1002 111
1003 643
1004 345

I would like to read column 2 in foo1 and replace with column 2 (where $1 in foo1 matches $1 in foo2) in foo2 if value is blank.
So output file

1000 345 456
1001 876 908
1002 111 786
1003 643 908
1004 345 234

Thanks

Code:

awk 'FNR==NR{a[$1]=$2;next}NF <3{print $1,a[$1],$2}NF>2{print}' foo2 foo1

-Devaraj Takhellambam

devtakh,

You forgot to check if the first field of Foo1 is an index in the array.

garethsays,

Assuming you have 3 fields in Foo1:

Code:

awk '
NR==FNR{a[$1]=$2;next}
a[$1] && NF==2{$2=a[$1] FS $2}
1' Foo2 Foo1

Alternatively:

Code:

$
$ perl -ne 'BEGIN{open(F,"foo2"); while(<F>){($a,$b)=unpack"a4xa3"; $ids{$a}=$b} close(F)}
> {($x,$y,$z)=unpack("a4xa3xa3"); print "$x $ids{$x} $z\n"}' foo1
1000 345 456
1001 876 908
1002 111 786
1003 643 908
1004 345 234
$
$

tyler_durden