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--- chown_and_chmod_examples [2016/08/10 09:03] – walkeradmin
+++ chown_and_chmod_examples [2023/03/09 22:35] (current) – external edit 127.0.0.1
@@ Line 30: / Line 30: @@
     -rw-r--r-- 1 himanshu friends 0 2012-05-22 20:03 tmpfile
 \\
+==== Change owner only if a file is owned by a particular user ====
+\\
+Using chown “–from” flag, you can change the owner of a file, only if that file is already owned by a particular owner.
+    # ls -l tmpfile
+    -rw-r--r-- 1 root friends 0 2012-05-22 20:03 tmpfile
+    # chown --from=guest himanshu tmpfile
+    # ls -l tmpfile
+    -rw-r--r-- 1 root friends 0 2012-05-22 20:03 tmpfile
+    # chown --from=root himanshu tmpfile
+    # ls -l tmpfile
+    -rw-r--r-- 1 himanshu friends 0 2012-05-22 20:03 tmpfile
+  * In the example above, we verified that the original owner/group of the file ‘tmpfile’ was root/friends.
+  * Next we used the ‘–from’ flag to change the owner to ‘himanshu’ but only if the existing owner is ‘guest’.
+  * Now, as the existing owner was not ‘guest’. So, the command failed to change the owner of the file.
+  * Next we tried to change the owner if the existing owner is ‘root’ (which was true) and this time command was successful and the owner was changed to ‘himanshu’.
+\\
+==== Copy the owner/group settings from one file to another ====
+    This is possible by using the ‘–reference’ flag.
+    # ls -l file
+    -rwxr-xr-x 1 himanshu family 8968 2012-04-09 07:10 file
+    # ls -l tmpfile
+    -rw-r--r-- 1 root friends 0 2012-05-22 20:03 tmpfile
+    # chown --reference=file tmpfile
+    # ls -l tmpfile
+    -rw-r--r-- 1 himanshu family 0 2012-05-22 20:03 tmpfile
+\\
+In the above example, we first checked the owner/group of the reference-file ‘file’ and then checked the owner/group of the target-file ‘tmpfile’. Both were different.  Then we used the chown command with the ‘–reference’ option to apply the owner/group settings from the reference file to the target file. The command was successful and the owner/group settings of ‘tmpfile’ were made similar to the ‘file’
+\\
+\\
+==== List all the changes made by the chown command ====
+    Use the verbose option -v, which will display whether the ownership of the file was changed
+    or retained as shown below.
+    # chown -v -R guest:friends linux
+    changed ownership of `linux/redhat/rh7' to guest:friends
+    changed ownership of `linux/redhat' retained to guest:friends
+    ownership of `linux/redhat_sym' retained as guest:friends
+    ownership of `linux/ubuntu_sym' retained as guest:friends
+    changed ownership of `linux/linuxKernel' to guest:friends
+    changed ownership of `linux/ubuntu/ub10' to guest:friends
+    ownership of `linux/ubuntu' retained as guest:friends
+    ownership of `linux' retained as guest:friends
+\\
+\\