Efficiently print a line deep in a huge log file

sed '1000000!d;q' < massive-log-file.log
Sed stops parsing at the match and so is much more effecient than piping head into tail or similar. Grab a line range using sed '999995,1000005!d' < my_massive_file

By: root
2009-01-26 11:50:00

1 Alternatives + Submit Alt

What Others Think

I prefer: sed -n '1000000p' massive-log-file.log
penthief · 599 weeks ago
Have you done tests? In my examples (line 10 mio from a 19 mio lines file) head|tail was faster. sed was only slightly faster if you write: head -n 10000001 | tail -n 2 0.9 sec utime, 2 sec clock time sed -n '10000000,10000001p' 1.7 sec utime, 2.2 sec clock time sed -n '10000000,10000001p;10000002q' 0.9 sec utime, 1.2 sec clock time Otherwise sed will parse until the end, what head|tail doesn't. Overall the time differences seem irrelevant. It's more a question of beauty. :-)
weidenrinde · 257 weeks and 1 day ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: