[Chapter 22] 22.21 How to Change File Ownership Without chown
Author: Jerry Peek, Tim O'Reilly & Mike Loukides
Date: 1998-08-04T21:40:43Z

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| Chapter 22 File Security, Ownership, and Sharing |

## 22.21 How to Change File Ownership Without chown

UNIX systems with disk quotas (24.17) won't let you change the owner (22.20) of a file; only the superuser can use chown. Here's a workaround for those systems.

1. The file's current owner should make sure that the new owner has write permission on the directory where the file is and read permission on the file itself:

   >     jerry% ls -ld . afile
   >     drwxr-xr-x   2 jerry    512  Aug 10 12:20 .
   >     -rw-r--r--   1 jerry   1934  Aug 10 09:34 afile
   >     jerry% chmod go+w .

2. The new owner (logged in as herself) should rename the file, make a copy, and delete the original file. If the new owner is there at the same time, su (22.22) is probably the fastest way to change accounts:

       -f
       jerry% su laura
       Password:
       laura% mv afile afile.tmp
       laura% cp -p afile.tmp afile
       laura% ls -l afile
       -rw-r--r--   1 laura   1934  Aug 10 09:34 afile
       laura% rm -f afile.tmp
       laura% exit
       jerry% chmod go-w .

The cp -p (18.15) command preserves the file's original permissions and last modification time. After the new owner (laura) is done copying, the old owner (jerry) takes away the directory's write permission again.

- JP

22.20 Why Can't You Change File Ownership Under BSD UNIX? |  | 22.22 The su Command Isn't Just for the Superuser