How does “cat << EOF” work in bash?

Question

I needed to write a script to enter multi-line input to a program (psql).

After a bit of googling, I found the following syntax works:

c         


        

Answer 1

Using tee instead of cat

Not exactly as an answer to the original question, but I wanted to share this anyway: I had the need to create a config file in a directory that required root rights.

The following does not work for that case:

$ sudo cat </etc/somedir/foo.conf
# my config file
foo=bar
EOF

because the redirection is handled outside of the sudo context.

I ended up using this instead:

$ sudo tee </dev/null
# my config file
foo=bar
EOF