I want to redirect both stdout and stderr of a process to a single file. How do I do that in Bash?
You can redirect stderr to stdout and the stdout into a file:
some_command >file.log 2>&1
See http://tldp.org/LDP/abs/html/io-redirection.html
This format is preferred than the most popular &> format that only work in bash. In Bourne shell it could be interpreted as running the command in background. Also the format is more readable 2 (is STDERR) redirected to 1 (STDOUT).
EDIT: changed the order as pointed out in the comments