Using variables in sed -f (where sed script is in a file rather than inline)

Question

We have a process which can use a file containing sed commands to alter piped input.

I need to replace a placeholder in the input with a variable value,

Answer 1

I am in agreement with sputnick. I don't believe that sed would be able to complete that task.

However, you could generate that file on the fly.

You could change the date to a fixed string, like __DAYOFWEEK__.

Create a temp file, use sed to replace __DAYOFWEEK__ with $(date +%Y).

Then parse your file with sed -f $TEMPFILE.

sed is great, but it might be time to use something like perl that can generate the date on the fly.