What does “/dev/null” mean at the end of shell commands

Question

What is the difference between the following commands?

ssh myhostname \"command1; command2;...commandn;\" 2>/dev/null
ssh myhostname \"command1; command2;         


        

Answer 1

'/dev/null' essentially means "into the void", discarded. The 2 you mention refers to error output, where it should be directed.