Hello all ,

I have wrote eventhandler script to edit smsd.conf file automatically via sed.
It is useful solution to disable / enable modems based on various conditions.
Here is code snippset

sed -i "/^\[$MODEM\]$/,/^queues/s/^queues\s*=.*$/queues = main/" /etc/smsd.conf

The script replaces some portion of smsd.conf file with aid of just in place editing feature of sed ( sed -i ).
This works fine.
However after such operation file permissions on smsd.conf file are changed and system admin has no ability to edit it manually.

Please advice , what is the proper way to edit file with storing file permissions unchanged.

Can you re-check this issue?

I just tried this using sed -i, and it did not change the file permissions. The file was 644 and smsd:dialout, and after sed -i was run by the root, permissions and ownership were the same. Changes to the file were made correctly, but it was just a single line change.

what is your sed version number ?

GNU sed version 4.1.2

may be this is version dependent feature. I will explore it.

Thanks !

Please close this post.
sed handles file permissins properly during inline editing.

my mistake.