Sequentially run commands in bash script

问题:

I need to run two commands sequentially in daemon mode (the commands will output the errors on stderr). The problem is that even I dump all the output in /dev/null, the second command (run_cmd2) cannot be invoked. Here is my script

#! /bin/bash
nohup ./run_cmd1 &> /dev/null &
nohup ./run_cmd2 &> /dev/null &

Any ideas? Thank you in advance.

回答1:

How about using a file to communicate state?

run_cmd2 will wait until a file exists before running

when run_cmd1 is done, it will create the said file.

at the end of its run the run_cmd2 will delete the file, so run_cmd1 can run again

Or maybe they talk to each other using a port?

Or maybe a semaphore?

For more details: http://www.tldp.org/LDP/tlk/ipc/ipc.html