代码如下
代码： 全选
#!/bin/bash
# spawn.sh
PIDS=$(pidof sh $0) # Process IDs of the various instances of this script.
P_array=( $PIDS ) # Put them in an array (why?).
echo $PIDS # Show process IDs of parent and child processes.
let "instances = ${#P_array[*]} - 1" # Count elements, less 1.
# Why subtract 1?
echo "$instances instance(s) of this script running."
echo "[Hit Ctl-C to exit.]"; echo
sleep 1 # Wait.
sh $0 # Play it again, Sam.
exit 0 # Not necessary; script will never get to here.
# Why not?
# After exiting with a Ctl-C,
#+ do all the spawned instances of the script die?
# If so, why?
# Note:
# ----
# Be careful not to run this script too long.
# It will eventually eat up too many system resources.
# Is having a script spawn multiple instances of itself
#+ an advisable scripting technique.
# Why or why not?按这个例子的意思是不按Ctl-C这个脚本是不会停止的
我运行出错：
指点指点6713 6701 6476 5561
3 instance(s) of this script running.
[Hit Ctl-C to exit.]
./spawn.sh: 6: Syntax error: "(" unexpected
