sudo date > output.txt
bash: output.txt: Permission denied
I want to write log message into file, but the permission denied even I add prefix sudo, But when I tried after making output.txt file and changing permission to 755, It works well.
How can I write log meesage without making file and changing permission?
simply like sudo date > output.txt --chmod 755 ?
date | sudo tee output.txt > /dev/null
This works because tee opens the output.txt and it is running as root. The > /dev/null is just to throw away the extra copy that tee would send to stdout.
The reason why sudo date > output.txt doesn't work is that the output redirection (the > output.txt) is done before the sudo date is started, and so runs with the current access rights.
A different approach would be to change the permissions on the current directory to allow the current user to create files. Doing this would mean that date > output.txt could work without needing sudo.
