I am playing around with a proc, trying to get it to append some data to the beginning of an existing file. With the value of “a” or “a+” for the access argument, I can get it to append at the end of the file. Does anyone know of a way to append the data to the beginning?
You can use seek to get the pointer to the beginning of the file. But I think any data written will over-write existing data, not prepend.
You might try something like this:
Code:
set new_data “this is new data, which should be prepended”
set filename foo.txt
set existing_data [read_file $filename]
write_file $filename ${new_data}${existing_data}
.
