why my bash shell session is exiting unexpectedly

Question

I am using putty to ssh into my Linux server. After I login using bash and I enter this command exec echo abc this causes my session to close. what is the reason for the session to close this way?

Answer 1

exec tells the shell to replace itself in memory with the program being executed. Consequently, the shell is no longer running after a successful exec.

If you want your shell back afterwards, the command needs to be

echo abc

not

exec echo abc