How to replace next word after a match in perl or sed expression?

roman Sztergbaum 0
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I'm trying to replace doxygen comment from a file with swift comments.

e.g: /// \param foo should became /// - Parameter foo: with foo

So far I have

gsed -i 's/\\param/\- Parameter/g' my_file or perl -pe 's/\\param/\- Parameter/g'

I'd like to replace the following word (foo) after my expression with word: (foo:)

I didn't manage to find a good expression for that. Ideally, something that work on Linux and macOS

sed perl
3 Answers

In perl you can capture and put back the word with $1 (first parentheses).

s/\\param\s+(.+)/- Parameter $1:/g

.+ will capture the rest of that line. If that is something you don't want, and just want to capture the first word, you can use \S+ or \w+ or whatever other character class that matches the characters you want to capture, e.g. [a-z_-]+.

In sed it is probably \1.

TLP0

Using sed

$ sed -E 's/\\(param)( [^ ]*)/- \u\1eter\2:/' input_file
/// - Parameter foo:
HatLess0

You could use pattern with a single capture group, and use that group with \1 in the replacement.

sed -E 's/\\param[[:space:]]+([^[:space:]]+)/- Parameter \1:/g' my_file

The pattern matches:

  • \\param Match \param
  • [[:space:]]+ Match 1+ spaces
  • ([^[:space:]]+) Capture group 1, match 1+ non whitespace chars

Output

- Parameter foo:

If you validated the output, then you can change sed -E to sed -Ei to do the replacement.

The fourth bird0
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