I'm trying to understand this shell cmd.
I understand that:
convox exec <pid> is going to execute the following cmd in the container with pid as the ID
< file.txt work redirects the content of file.txt file as input to the convox cmd
> file.txt overwrite the file context with whatever is on the left of that > redirect operator
Then the question is what does that
cat - do? How does the content of my local file.txt get passed to the command that is going to run within the container?