why sed replace + redirection deletes my file?

Question

I am using sed to search and replace two strings in a file in bash (GNU sed)

This is the file after

-rw-r--r-- 1 websync www-data 4156 mar 27 12:56 /         


        

Answer 1

sed reads your files in as a stream and outputs a stream as well. As soon as you perform the redirection into your file the contents are overwritten, and since that file is being read as a stream, it hasn't even started being read by sed yet. When sed does start reading the file it is empty so it finishes immediately with no output.

Use -i, to do an in-place edit, instead:

sed 's/www-test/www/g' -i /home/websync/tmp/sitio-oficial/sitios/wp-config.php