Question

I have a small issue here, I need to be able to read a file of unknown size it could be a a few hundred lines or many more the log files change all the time and depending on when i check. I would like to have a method that is in php or in linux that i can read a range of lines from a file. I dont want to have to read the entire file in to php memory then remove the lines because the file may be larger then the allowed memory of php.

I also want it to be using default php modules or default linux tools dont want to need to install anything because it needs to be portable.

Edit:

For the linux based options I would like to be able to supply more then one range, i may need to get a few different ranges of lines I know how to do it in php by not in linux and to avoid reading past lines i have already read?

Answer 1

With awk:

awk 'NR>=10 && NR<=15' FILE

With awk (two ranges):

awk 'NR>=10 && NR<=15 || NR>=26 && NR<=28' FILE

With ed:

echo 2,5p | ed -s FILE

With ed and two ranges :

echo -e "2,5p\n7,8p" | ed -s FILE

Last but not least, a sed solution with two ranges (fastest solution, tested with time):

sed -n '2,5p;7,8p' FILE