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regexcommand-linegrepcut

Translate cut code to grep regex code for locating and returning up to the first hyphen

I have a list of filenames similar to the following:

NAME - Something something something
ANOTHER NAME - More stuff
THIRD - This is a title
FOURTH - This is a title - With an extra hyphen
FIFTH NAME - And some more

What I would like is to grab just the names up to the first hyphen. That is, my results should be:

NAME
ANOTHER NAME
THIRD
FOURTH
FIFTH NAME

I was able to accomplish this via cut -d'-' -f1 but I was wondering what would be a way to translate this into a grep command?

I have tried expressions like grep -o "^[[:upper:]]* -" but I run into issues when there is a second hyphen contained in the name (e.g. FOURTH) and also with names that have more than word (e.g. ANOTHER NAME and FIFTH NAME).

Solution

  • You can use the extended flavour, use anchor to the beginning of the line and match every character until if finds a dash, like:

    grep -oE '^[^-]*' infile

    It yields:

    NAME 
ANOTHER NAME 
THIRD 
FOURTH 
FIFTH NAME