how to write a c/c++ variable to shell script?

Question

I want to send the C/C++ variable into my shell script, but tried many ways on the Internet, seems not working, could you help me with my code? C++ code:

void test::addroute(){
string test1=ip_address;
}

my shell script:

#!bin/sh
ip rule add from $test1 lookup $eth0_table

how to send the test1 to here?

It very much depends on your OS and on the particular use case (why do you need that? how many variables are passed? What kind of variables do you need?) — Yksisarvinen, Dec 04 '19 at 12:45
You can run `ip` from your C code directly. e.g. `system("ip rule add...");` — rustyx, Dec 04 '19 at 12:50

score 0 · Answer 1 · answered Dec 04 '19 at 12:58

You can print the variable content on stdout and include it with using subcall $().

So if you program will be called test. Just call it like

ip rule add from $(test) lookup ...

If you need more complex output, make it a csv-like format and use it like this:

output="$(test)"
first="$(echo ${output}|cut -d ';' -f 1 )"
second="$(echo ${output}|cut -d ';' -f 2 )"
ip rule add from "${first}" lookup "${second}"

Don't know if changing variables directly would make a bit of chaos.

how to write a c/c++ variable to shell script?

1 Answers1