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BenMorel
Asked: 2013-05-21 08:54:41 +0800 CST

Make recursive chmod faster

  • 772

I have an installation script that unzips a directory, then recursively chmods its contents.

I'm surprised it takes almost 10 times the time it takes to unzip, to run the following two commands:

find $dir -type f -exec chmod a+r "{}" \;
find $dir -type d -exec chmod a+rx "{}" \;

Am I doing something wrong, is there a faster way to change the chmod of all files and directories?

linux

4 Answers

  1. Best Answer

    You can get rid of the find commands by using chmod's X flag:

    execute/search only if the file is a directory or already has execute permission for some user (X)

    This allows you to set the same permissions on files and directories, with directories additionally being executable, with a single command:

    $ chmod -R a+rX $dir
    • 13

  2. You could do the following (assumming Linux):

    cd $dir
chmod -R a+r .
find . -type d -print0 | xargs -0 chmod a+x

    This should be much faster than the combination of the two commands you indicated in your question.

    • 5

  3. Use tar instead. Specifically with the -p, --preserve-permissions, --same-permissions flag.
    You won't can't directly zip it, but -z, --gzip, -j, --bzip2 or -J, --xz ought to work well enough. If you really must have zip it's only a | away.

    • 2

  4. Given your command, I'm thinking you are spending time waiting for find not chmod.

    Try:

    chmod -R a+r $dir

    The "-R" means recursive

    When you run the unzip and other commands preface them with

    time

    To get a measurement of the time spent for the various commands.

    • 0