Question

i have a file and would like to copy some entries that satisfy certain conditions.
For example

myfile
chr1 a b c
chr2 a b c
chr3 x y z

I would like to copy lines whose first column starts with chr1 and i want to copy it n times.

myfile
chr1 a b c
chr1 a b c
chr1 a b c
chr2 a b c
chr3 x y z

Answer 1

Something like this would be fine?

awk '{if ($1 == "chr1"){print; print;} print;}'

It will print 2 more times the lines that start with chr1

…and with a for loop:

awk '{if ($1 == "chr1"){ for(i=1;i<=2;i++){ print; } } print;}'

ok, this should be it

#!/usr/bin/awk -f

BEGIN{
    while ((getline < "conditions") > 0){
        cond[$1] = $2
    }
}
{
    print;
    for (i=0; i<cond[$1]; ++i){
        print;
    }
}

given a file named “conditions” like this:

chr1 5
chr2 3

and your example (with chr1, chr2 etc on different lines) as an input

it’ll print the chr1 line 6 times, the chr2 line 4 times and the chr3 line 1 time