How to redirect both stdout and stderr to a file

The simplest syntax to redirect both is:

command &> logfile

If you want to append to the file instead of overwrite:

command &>> logfile

You can do it like that 2>&1:

 command > file 2>&1

If you want to log to the same file:

command1 >> log_file 2>&1

If you want different files:

command1 >> log_file 2>> err_file