22.8 The Handy chmod = Operator

Let's say you have a set of files. Some are writable by you, others are read-only. You want to give people in your group the same permissions you have - that is, they can write writable files but can only read the read-only files. It's easy with an underdocumented feature of chmod :

% 

chmod g=u *

That means "for all files ( * ), set the group permissions ( g ) to be the same as the owner permissions ( u )." You can also use the letter o for others, which is everyone who's not the owner or in the owner's group. Article 22.2 explains these categories.

If your chmod has a -R (recursive) option, you can make the same change to all files and directories in your current directory and beneath. If you don't have chmod -R , use this find ( 17.10 ) :

% 

find . -exec chmod g=u {} \;

The cpmod ( 22.16 ) program on the CD-ROM can copy all file permissions.