What these two lines does? about mi-centos-7 HOT 1 OPEN

       set [--abefhkmnptuvxBCHP] [-o option] [arg ...]
...
              -e      Exit  immediately  if  a  simple  command (see SHELL
                      GRAMMAR above) exits with a  non-zero  status.   The
                      shell  does  not  exit  if the command that fails is
                      part of the command  list  immediately  following  a
                      while  or  until  keyword, part of the test in an if
                      statement, part of a && or || list, or if  the  com-
                      mand's return value is being inverted via !.  A trap
                      on ERR, if set, is executed before the shell  exits.
...
              -o option-name
...
                      pipefail
                              If set, the return value of  a  pipeline  is
                              the value of the last (rightmost) command to
                              exit with a non-zero status, or zero if  all
                              commands  in the pipeline exit successfully.
                              This option is disabled by default.
...
              -u      Treat unset variables as an  error  when  performing
                      parameter  expansion.   If expansion is attempted on
                      an unset variable, the shell prints  an  error  mes-
                      sage, and, if not interactive, exits with a non-zero
                      status.

set -e
cp foo bar
if (( $? != 0 )); then
    echo ouch
fi

if ! cp foo bar; then
    echo ouch
fi

cat /etc/shadow | awk -F: '$2 == "" { print $1 }' > lock_these_accounts