I am a bit stumped by this. I am no expert at sed/awk/grep, though I can usually find my way around... youngka@vadmin:~/www/nsr_19_data$ grep -iE '^[[:digit:]]+~[0-9 ...

I love chaining commands as much as anyone, and sed, awk, grep, and perl are some of my best friends. However, remember that, in *nix, each command runs in its own process, the resources required for ...