UNIX for Dummies Questions & Answers

$1 is the first field of the file..

I suppose a simple shell script could count lines read and print thos modulo 100 = 1, 2, or 0.

Code:

ct=0
while read l
do
 if (( ct % 100 == 1 ))
 then
  echo "$l"
 fi
done <in_file

If you don't like/have pipes <(...), you can collect each 300 lines in an array and print them out in your order.

You could prefix each line with the order you need them in (1, 4, 7, . . . 298, 2, 5, 8, . . . 299, 3, 6, 9, . . . 300, 301, 304, . . . .), sort -n them all and process the output three lines into one:

Code:

while read n l1
do
 read n l2
 read n l3
 echo "$l1 $l2 $l3"
done

It'd make a handy C app, just give it a width and length, and it can fputs the M lines to N tmpfile() FILE*'s, rewind, print, rewind, repeat.