Sourcing a script using QProcess

Mark81

Hi! I want to execute a bash script from my application using QProcess. Because the script exports some env vars I need to "source" it. Example:

cat myscript.sh
#!/bin/sh
echo Hello World
export MYVAR=blablabla

here my Qt application:

QProcess p;
p.start("myscript.sh");

executes the script, but of course no vars are exported to the current shell. But:

p.start("source myscript.sh");

doesn't execute the script at all, despite no errors are returned. I said "doesn't execute" because waitForStarted() fails and "Hello world" isn't echoed.

Where is my mistake?

mrjj

Hi
is source a standalone program/command ?
else it wont work as QProcess
have no idea how to run it
if internal bash command.
( I think )
maybe:
Process.start("bash", QStringList() << "-c" << "source" << "myscript.sh ");

jsulm

This post is deleted!

SGaist

Hi,

I haven't tested source with QProcess but in any case the correct call would rather be:

p.start("source", QStringList() << "/path/to/myscript.sh");

Give the full path to myscript.sh. You are likely using a shadow build so myscript.sh will not be in the same folder as your application.

Mark81

@SGaist
I tried like you suggested but the behavior is the same.

SGaist

Try with p.start("bash", QStringList() << "-c" << "\"\"source /path/to/test.sh\"\"");

Mark81

@mrjj
In this way the process (bash, or /bin/sh in my case) starts but it immediately ends with exit value 2 without executing the script.
QProcess returns no error.

Mark81

@SGaist
The process runs and the exit code is 0, but the script is not executed. By the way if I try to execute the following on prompt:

/bin/sh -c ""source /path/to/test.sh""

it does "nothing" (I mean no errors nor echo output).

SGaist

How are you checking that it does nothing with QProcess ?

In the console version you have too much quotes it should only be bash -c "source /path/to/test.sh"

Mark81

@SGaist

How are you checking that it does nothing with QProcess ?

The env vars are not exported and there is no echo.

In the console version you have too much quotes it should only be bash -c "source /path/to/test.sh"

Yes, in this way the echo is shown but the vars are not exported. It's the same as run the script directly without sourcing it. But it's beyond my knowledge to understand why.

mrjj

Can I ask silly question?
If you run bash first, wont the export be in that instance of bash?
source test.sh;echo $MYVAR
does as expected
but not with bash first.

SGaist

On OS X putting the echo call inside the "command string" worked.

I'm reading stdout using readAllStandardOutput

Mark81

@SGaist
Ok, I will try using readAllStandardOutput() too. But also the env vars are correctly exported?

jsulm

You can set the environment using

QProcess::setProcessEnvironment(const QProcessEnvironment & environment)

You can get the environment of your current process via

QProcessEnvironment::systemEnvironment()

SGaist

@Mark81 Yes both the Hello World and content of the variable were shown. Again it's on OS X with a recent version of bash.