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Recursively rename files using find and sed

Asked 2011-01-25T13:08:51.510
103

I want to go through a bunch of directories and rename all files that end in _test.rb to end in _spec.rb instead. It's something I've never quite figured out how to do with bash so this time I thought I'd put some effort in to get it nailed. I've so far come up short though, my best effort is:

find spec -name "*_test.rb" -exec echo mv {} `echo {} | sed s/test/spec/` \;

NB: there's an extra echo after exec so that the command is printed instead of run while I'm testing it.

When I run it the output for each matched filename is:

mv original original

i.e. the substitution by sed has been lost. What's the trick?

bash scripting sed find replace
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This happens because sed receives the string {} as input, as can be verified with:

find . -exec echo `echo "{}" | sed 's/./foo/g'` \;

which prints foofoo for each file in the directory, recursively. The reason for this behavior is that the pipeline is executed once, by the shell, when it expands the entire command.

There is no way of quoting the sed pipeline in such a way that find will execute it for every file, since find doesn't execute commands via the shell and has no notion of pipelines or backquotes. The GNU findutils manual explains how to perform a similar task by putting the pipeline in a separate shell script:

#!/bin/sh
echo "$1" | sed 's/_test.rb$/_spec.rb/'

(There may be some perverse way of using sh -c and a ton of quotes to do all this in one command, but I'm not going to try.)

answered 2011-01-25T13:56:24.360

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