bash pull certain lines from a file

bash file-io

sed can do the job...

sed -n '100000,125000p' input

EDIT: As per glenn jackman's suggestion, can be adjusted thusly for efficiency...

sed -n '100000,125000p; 125001q' input

bash file-io

I'd use awk:

awk 'NR >= 100000; NR == 125000 {exit}' file

For big numbers you can also use E notation:

awk 'NR >= 1e5; NR == 1.25e5 {exit}' file

EDIT: @glenn jackman's suggestion (cf. comment)

bash file-io

You can try a combination of tail and head to get the correct lines.

head -n 125000 file_name | tail -n 25001 | grep "^$i "

Don't forget perl either.

perl -ne 'print if $. >= 100000 && $. <= 125000' file_name | grep "^$i "

or some faster perl:

perl -ne 'print if $. >= 100000; exit() if $. >= 100000 && $. <= 125000' | grep "^$i "

Also, instead of a for loop you might want to look into using GNU parallel.

CodeHunter