Bash脚本：如何将参数传递给另一个脚本中正在运行的脚本的函数？

Question

I am trying to call a function of a running script from another, and then pass to it an argument (in runtime)

// Original script

#!/bin/bash

VALUE_OF_EXIT_CODE=256

/bin/bash /home/dev/runningScript.sh arg1 arg2

# some code
doSomething ($VALUE_OF_EXIT_CODE) 

// running script

#!/bin/bash

function doSomething(){
     EXIT_CODE=$1
}

while(//something)
do
if [ "$EXIT_CODE" == 0 ]; then
     echo "normal exit => OK"  
     exit 0
fi
# If the exit code is not 0, then there was a error.
if [ "$EXIT_CODE" > 0 ]; then
    echo "Error => $EXIT_CODE"
    exit $EXIT_CODE 
fi
done

I want that the exit_code that I set in the original script, pass to the running script so this can evaluate it, and continue doing whatever has to do or EXIT.

Answer 1

Bash does not work that way. Here is what you should do:

1. Write the VALUE_OF_EXIT_CODE into a temporary file say tmp.
2. If you know the name of the running script's file, you can use pidof to get its pid.
3. Then use `kill - ' to indicate to the script that something has become available for it to do.
4. Your running script should have been coded to read from the tmp file. It should read that value and do whatever it has to do.

Yet another method would be to create a named pipe using mkfifo . Your running script should read from the pipe as its STDIN while your "another" script could write to it as its STDOUT.

There may be other ways of passing information between two different running bash scripts but multi-threaded programming in bash is still a long way to go.

Answer 2

This is the wrong way round, in my opinion. It would be easier to make what you call the "running script" start the "original script", instead of vice-versa.

Then you can read the exit code with $? , and call a function with it:

myFunction $?

Answer 3

For this kind of functionality, every language relies on interprocess messaging . In bash it always is a bit hackish because it is not "cooked&ready".

I tried to change as little as possible to your code (did fix some syntax though).
You have the possibility now to choose your IPC mechanism: file or named pipe on ram or disk. sockets are also possible and even the inotify kerneldaemon could be used.

This one works with a named pipe in tmpfs and with a signal .

// Original script

#!/bin/bash
mkfifo "/tmp/$$" ; exec 3<>"/tmp/$$"  
doSomething() { echo "$1" >&3 ; pkill -SIGUSR1 "runningScript.sh" ;}


VALUE_OF_EXIT_CODE=256

/home/dev/runningScript.sh $arg1 $arg2 &


# some code

doSomething "$VALUE_OF_EXIT_CODE" 

// running script

#!/bin/bash

trap "read EXIT_CODE <&3" SIGUSER1

while something
do
if [ $EXIT_CODE = 0 ]; then
     echo "normal exit => OK"  
     exit 0
fi
# If the exit code is not 0, then there was a error.
if [ $EXIT_CODE -gt 0 ]; then
    echo "Error => $EXIT_CODE"
    exit $EXIT_CODE 
fi
done