Search and replacing a string on specific file extensions

Question

I have this bash:

  replace="s/AAAA/BBBB/g";
  find myDirectory/. -type f -print0 | xargs -0 sed -i $replace;

that will recursively scan myDirectory tree and replace all occurrences of AAAA with BBBB on the files there.

But I want to limit this to happen on files of specific extensions, for example, .txt, .read, .po

How do I impose this limit?

Answer 1

You can use the -name option for find to restrict matches based on filename.

find myDirectory/. -type f -name '*.txt' -print0 | xargs -0 sed -i "$replace"

For multiple extensions, you can use -o (or) and group them with ().

find myDirectory/. -type f \( -name '*.txt' -o -name '*.read' \) -print0 | xargs -0 sed -i "$replace"

Another improvement that can be made is using -exec instead of xargs. This is more portable and eliminates a subshell.

find myDirectory/. -type f -name '*.txt' -exec sed -i "$replace" {} +

Answer 2

Add these settings to your .bashrc:

shopt -s extglob globstar

extglob turns on some additional patterns, including the @(…) construct for disjunction. globstar turns on **/ which traverses directories recursively.

Then you don't need to use find:

sed -i "$replace" mydirectory/**/*.@(txt|read|po)

In zsh, you don't need any special option, just run

sed -i $replace mydirectory/**/*.(txt|read|po)

If you have a lot of files, you may see a message like “command line length limit exceeded”. But the limit is very high on modern Linux systems, you're unlikely to encounter it.

Answer 3

From the manual (man find), look under operators by typing /OPERATORS then Enter.

find myDirectory/ -name '*.txt' -o -name '*.txt' -o -name '*.read' -o -name '*.po'