find grep on Mac OS X

On linux machines I search files using find, egrep and xargs as follows:

  find . -name "*.cpp" | xargs -i egrep -iHn "some search string" {}

this outputs any matches with the filename and number and also disables case dependency.

On my Mac it doesn't work. I tried reverting to egrep -r (to search recursively) instead, but that doesn't work. It just fails silently too. I tried installing findutils with brew to see if that helped, as often gnu tools are more up to date in brew than in the Apple version, but that didn't help.

So after some fiddling I found that the syntax below works:


  find . -name "*.cpp" | xargs egrep -iHn "some search string"

Only subtly different!

Actually, hold up, this does not work for filenames that have spaces in them. :(

Try this instead:

find . -type f -print0 | xargs -0 egrep -iHn "some search string"

J.

rgrep on windows 7 for emacs

I lost an hour configuring this, so seems worthy of a blog post.

A fresh install of emacs for windows will have functionality that does not work because it depends on unix style utilities.

One very useful example is the command rgrep, which searches files recursively through subfolders looking for a regular expression in those files.

Under the hood it uses the unix command line tools find, and egrep. Unfortunately the windows version of find takes entirely different parameters and will not function. In fact you will get an error that looks like this:

FIND: Wrong parameter format

Using the set of native ports of Unix command line tools UnxUtils you can easily fix this:

1. Download the zip file and extract it to c:\unxutils
2. Add the following path to the very front of your path by editing your system environment variables C:\unxutils\usr\local\wbin\;

That's it. You can run rgrep now and hopefully you're up and running.

If not make sure you have restarted emacs so it picks up the new setting of PATH. Open a shell in emacs and type 'find --version'. You should see something like this if your path is configured correctly:

c:\find --version

find --version

GNU find version 4.1

and if not you will see:

C:\Windows\system32>find --help

FIND: Parameter format not correct