Question

i have some data files, and i need to pull some info out. i’d like to use a single awk script to get data out, so i can suck some data into bash arrays.

for this, let’s assume i need the following (1-indexed):
– i need awk to print column one on lines 2, 3, and 4
– i need awk to print columns 1, 2, and 3 on lines 8 and over. but i want all of the column ones printed before the column twos, and the column twos before the column threes.

using the following data example:

abc
def
ghi
jkl
mno
1a1
2b2
11 22 33 44
55 66 77 88
99 00 12 13
14 15 16 17

i would want awk to print the string:

def ghi jkl 11 55 99 14 22 66 00 15 33 77 12 16

i created the following, which i thought would work, but i am getting an error saying “END bocks must have an action part”.

awk '
BEGIN {i=0;}
{
   if ((NR >= 2) && (NR <= 4))
      print $1;
   if (NR >= 8)
   {
      col1_arr[i] = $1;
      col2_arr[i] = $2;
      col3_arr[i] = $3;
      i++;
   }
}
END
{
   for (j = 0; j < i; j++)
       print col1_arr[j];
   for (j = 0; j < i; j++)
       print col2_arr[j];
   for (j = 0; j < i; j++)
       print col3_arr[j];
}' /path/to/my/file

thanks ahead of time.

Answer 1

This should work –

awk '
BEGIN{i=0;}
NR>=2 && NR<=4 {printf $1" "} 
NR >=8 {col1[i]=$1;col2[i]=$2;col3[i]=$3;i++;} 
END{for (i=0;i<=NR-8;i++) printf col1[i]" "; for(i=0;i<=NR-8;i++) printf col2[i]" ";for (i=0;i<=NR-8;i++) printf col3[i]" "}' INPUT_FILE


[jaypal:~/Temp] cat data
abc
def
ghi
jkl
mno
1a1
2b2
11 22 33 44
55 66 77 88
99 00 12 13
14 15 16 17

[jaypal:~/Temp] awk '
BEGIN{i=0;}
NR>=2 && NR<=4 {printf $1" "} 
NR >=8 {col1[i]=$1;col2[i]=$2;col3[i]=$3;i++;} 
END{for (i=0;i<=NR-8;i++) printf col1[i]" "; for(i=0;i<=NR-8;i++) printf col2[i]" ";for (i=0;i<=NR-8;i++) printf col3[i]" "}' data
def ghi jkl 11 55 99 14 22 66 00 15 33 77 12 16