Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm looking for a way to grep things like: i log for E M, i 1 f x i 0, I xi 1, 3 1,. simply based on number of characters.

Nothing in that hypothetical output is longer than three characters. This hypothetical one-liner would look something like, grep -v [:alnum:] > {3}. (Except I just don't know how to write that in grep syntax.)

share|improve this question
Do you want to match characters like , and . as part of a word? – user13742 Feb 24 '12 at 17:31
up vote 10 down vote accepted
grep -o -w '\w\{1,3\}' data

Options are:

  • -o print only matched words
  • -w match only whole words

It matches only words (in grep \w = [[:alnum:]] = [A-Za-z0-9]) of length from 1 to 3 (specified by {1,3})

share|improve this answer
thanks. the basic syntax of your answer is what i needed, and i ended up just using grep '\w\{3}' data and the same command with grep -v.. – ixtmixilix Feb 26 '12 at 21:29

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.