file_1 contents:
aaa 111 222 333
bbb 444 555 666
ccc 777 888 999
file_2 contents:
ddd
eee
fff
how do i copy only part of the text from file_1 to file_2
so that file_2 would become:
ddd 111 222 333
eee 444 555 666
fff 777 888 999
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1 Answer
Try with awk:
awk 'NR==FNR{a[FNR]=$2FS$3FS$4;next} {print $0, a[FNR]}' file_1 file_2
Explanation:
NR is the current input line, FNR is the number of input line in current file, you can see that by
$ awk '{print NR,FNR}' file_1 file_2
1 1
2 2
3 3
4 1
5 2
6 3
So, the condition NR==FNR is only true when reading the first file, and that's when the columns $2, $3, and $4 get saved in a[FNR]. After reading file_1, the condition NR==FNR becomes false and the block {print $0, a[FNR]} is executed, where $0 is the whole line in file_2.
2 Comments
ray
what if the text to copy are not length-fixed? i mean, like a text string which have variable text fields not necessarily 4, and i want to copy all the text field except the first.
user2314737
@ray Same story. The variables
$1, $2, etc are the fields in the line. All awk cares about is the field separator, that by default is is one or more whitespaces. The fields themselves can be strings of variable length.