使用C ++或Bash / Shell脚本评估后台linux命令的输出

Question

Question: Using C++ or a bash/shell script, how can I evaluate output of a long running linux process?

Example:

root@example.com~# iw event
(This command will run until manually killed.) 
(It will output data that I will want to read and parse line by line.)

What is the most efficient way to evaluate the std output of this command when a new line is added to its buffer?

For example: iw event will output a line that says:

new station: 0e:0e:20:2d:20

I want to detect "new station" and run another command with the mac address. IE:

./myProgram -mac 0e:0e:20:2d:20

Thanks!

Answer 1

If you run the command as shown, all output will go to stdout and display on the terminal. To capture the output you have a few options:

• Pipe the output to your monitor program, as in iw events | yourmonitorprogram iw events | yourmonitorprogram which then reads stdin. iw should probably be modified to use unbuffered output.
• Write the output of iw to a file and then use the same technique as the tail -f command to poll the file periodically
• Have iw write to a named pipe or socket and have your monitor program read from that pipe or socket. This option requires modification to iw .

The simplest option is the first one