How to change the permissions on Linux

Question

How do I set all *.java files in the current directory and all its sub directories to have read permission to all users?

I also want to set all files of at least 1 kilobyte in size in the current directory and all sub directories to have a group of admin.

Answer 1

Alternative: To set read permission for all .java files in the current directory, use this command:

chmod -R 444 *.java

To set all files of at least 1 kilobyte in size in the current directory and all sub directories to have a group of admin.

find /yourdirectorypath -size +1k -exec chgrp admin {} \;

Note: the "-R" indicates recursive which will cover your sub directories as well

Answer 2

How do I set all *.java files in the current directory and all its sub directories to have read permission to all users?

In bash ≥4.0 and zsh:

chmod a+r ./**/*.java

On any POSIX-compliant system (i.e. any non-antique unix variant and more):

find . -name '*.java' -exec chmod a+r {} +

Set all files of at least 1 kilobyte in size in the current directory and all sub directories to have a group of admin.

In zsh:

chgrp admin ./**/*(.L+1023)

On any POSIX-compliant system:

find . -type f -size +1023c -exec chgrp admin {} +

Answer 3

Use find and xargs

find . -name \*.java | xargs chmod o+r

or

find . -name \*.java -print0 | xargs -0 chmod o+r

The second version handles spaces in file or directory names.

You may need to fix directory permissions as well.

find . -type d -print0 | xargs -0 chmod o+rx

You can avoid updating permissions which are already correct. Check the man page for find and review the section on permissions.

Answer 4

To set read permission for all .java files in the current directory, use this command

chmod +r *.java