What is </dev/null in bash?

Question

In bash, standard (1) and error (2) output can be re-routed and discarded with:

>/dev/null 2>&1

But the following example does s

Answer 1

is used to avoid the script wait for input.

Quoting from the usage of < /dev/null & in the command line:

< /dev/null is used to instantly send EOF to the program, so that it doesn't wait for input (/dev/null, the null device, is a special file that discards all data written to it, but reports that the write operation succeeded, and provides no data to any process that reads from it, yielding EOF immediately). & is a special type of command separator used to background the preceding process.

So the command:

nohup myscript.sh >myscript.log 2>&1 

will move to background the command, outputing both stdout and stderr to myscript.log without waiting for any input.