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On OSX you can have tags which allows you to identify different categories of files. Here are two text files with different tags when viewed in Finder:

enter image description here

I have a large number of these files and have written a bash script to make several edits on these files. So, for instance I do:

$ sed 's/old text/new text/' file1.txt > /tmp/foo.txt
$ cp -p /tmp/foo.txt file1.txt

in which case I get the desired file content but loose the tags:

enter image description here

Question: How do I copy the tags from the original file to the edited file?

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    I believe that in this specific use case you can use "sed -i" for inline editing. This will keep tags in place. Not posting as answer as it doesn't answer part about copying tags and you can't always use inline editing. – pbm Mar 1 '15 at 23:41
  • @pbm: I was not able to get the "sed -i" to work on MacOS 10.9.5 and still keep the tags. The "-i" required a file extension that was used to rename the current file and hence the meta data was lost. – Peter Grill Mar 2 '15 at 1:26
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When you run > /tmp/foo.txt, you are overwriting the contents of /tmp/foo.txt with the output of sed 's/old text/new text/' file1.txt. Since /tmp/foo.txt doesn't exist when you run this command, bash will create that file for you and then write it.

Then, when you use the -p flag to cp, you are copying the permissions and attributes of /tmp/foo.txt to file1.txt and overwriting it in the process.

Instead, what you want to do is overwrite the contents of file1.txt with the contents of /tmp/foo.txt, which should sound familiar. Run

sed 's/old text/new text/' file1.txt > /tmp/foo.txt
cat /tmp/foo.txt > file1.txt

Note that this doesn't copy any permissions or attributes from file1.txt to /tmp/foo.txt or vice versa - you are maintaining the existing metadata for file1.txt, but modifying the content.

In this specific instance, you could also just use sed -i as pbm suggested.

  • Glad it was so simple. – Peter Grill Mar 2 '15 at 1:27

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