Bash read/write file descriptors — seek to start of file

Question

I tried to use the read/write file descriptor in bash so that I could delete the file that the file descriptor referred to afterward, as such:

F=$(mktemp)
ex         


        

Answer 1

When you open a file descriptor in bash like that, it becomes accessible as a file in /dev/fd/. On that you can do cat and it'll read from the start, or append (echo "something" >> /dev/fd/3), and it'll add it to the end. At least on my system it behaves this way. (On the other hand, I can't seem to be able to get "cat <&3" to work, even if I don't do any writing to the descriptor).