3

I have a file with many curly bracketed words, ex. {test1}, {test2} - how would I grep for these words and output a distinct list of them?

output example:

{test1}
{test2}

I've tried this which didn't work:

grep -o {.*} file.xml  | sort | uniq

UPDATE

Actually - this seems to have worked:

grep -oP '{.*?}' file.xml | sort | uniq
  • Welcome to Unix & Linux! If you've determined your own solution you can write it up as the answer. – slm Jul 22 '13 at 14:59
4

There are two problems with your first attempt. {.*} contains special characters which need to be protected from expansion by the shell; put quotes around the pattern. Also, {.*} matches the longest brace-delimited text on the line, so if you have a line containing hello {test1} world {test2} howdy then the output is {test1} world {test2} becaause .* matched test1} world {test2.

The following will output only what is between brackets.

grep -o -e "{[^}]*}" 

My original formulation used "{.*}", but with that the widest bracket found within a line, not the smallest one would be returned...

  • 1
    Good, but why -e? – frostschutz Jul 22 '13 at 15:00
  • Just an old habit. I know, that it's optional as long as there's only one pattern. – soulsource Jul 22 '13 at 15:03
  • @soulsource Can you explain this syntax? {[^}]*} Thanks! – tommy.carstensen Mar 16 '18 at 14:15
  • The [ ] brackets match any character that's written between them. Followed by a * this matches an arbitrary number of characters from the list of characters between the [ ] brackets. The list of characters between the [ ] is in this case ^}, meaning: "any character that's not a }". – soulsource Mar 17 '18 at 15:34
  • Thanks! It was the ^} I didn't understand. Thanks for the explanation! – tommy.carstensen Mar 18 '18 at 2:31

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