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imaginative
Asked: 2013-09-13 15:57:21 +0800 CST

How to properly pipe find with grep and cp in this use case

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I am interested in recursively grepping for a string in a directory for a pattern and then cp'ing the matching file to a destination directory. I thought I could do something like the following, but it doesn't seem to make sense with linux's find tool:

find . -type f -exec grep -ilR "MY PATTERN" | xargs cp /dest/dir

Is there a better way of going about this? Or a way that even works would be a solid start.

linux

4 Answers

  1. Best Answer

    Do man xargs and look at the -I flag.

    find . -type f -exec grep -ilR "MY PATTERN" {} \; | xargs -I % cp % /dest/dir/

    Also, find expects a \; or + after the -exec flag.

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  2. xargs reads its standard input and puts them at the end of the command to be executed. As you've written it, you would end up executing

    cp /dest/dir sourcefile1 sourcefile2 sourcefile3

    which is backwards from what you want.

    You could use the -I option to specify a placeholder for xargs, like this: xargs -I '{}' cp '{}' /dest/dir.

    Also, find takes care of the recursion, so your grep does not need -R.

    Final solution:

    find . -type f -exec grep -il "MY PATTERN" '{}' + | xargs -I '{}' cp '{}' /dest/dir
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  3. I don't think you need find. Recursive grep:

    grep -rl "MY PATTERN" .
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  4. None of the examples above takes into account the possibility of grep's -l generating duplicated results (files with the same name, but in different places), and therefore find's exec's hook overwriting files in the destination directory.

    An attempt to solve this:

    $ tree foo
foo
├── bar
│   ├── baz
│   │   └── file
│   └── file
├── destdir
└── file

3 directories, 3 files

$ while read a; do mv $a foo/destdir/$(basename $a).$RANDOM; done < <(grep -rl content foo)

$ tree foo
foo
├── bar
│   └── baz
└── destdir
    ├── file.10171
    ├── file.10842
    └── file.25404

3 directories, 3 files
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