self-exec.sh

Shall高级编程

#!/bin/bash
# self-exec.sh

echo

echo "This line appears ONCE in the script, yet it keeps echoing."
echo "The PID of this instance of the script is still $$."
#     Demonstrates that a subshell is not forked off.

echo "==================== Hit Ctl-C to exit ===================="

sleep 1

exec $0   #  Spawns another instance of this same script
          #+ that replaces the previous one.

echo "This line will never echo!"  # Why not?

exit 99                            # Will not exit here!
                                   # Exit code will not be 99!