Escaping bash variable [closed] - linux

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I'm a bit stuck with this. I'm delaring a variable at the top of my script, then I am creating a file as part of my script:
app="testing"
cat <<EOF >/etc/init.d/test
#!/bin/bash
args="--emperor $APPCONF/test/$APP.ini"
EOF
It doesn't seem to work though, it seems on the $app variable. Must I do something to this variable to get it to display it's value, "testing" inside the file I create?

Answer 1

Use consistent case. variable names are case sensitive.

Answer 2

Let's say you were doing this the Right Way. You'd want to store your data in an array:
args=( --emperor "${appconf}/test/${app}.ini" )
and then convert it to a string for embedding:
printf -v args_str '%q ' "${args[#]}"`
...and use that string inside your heredoc:
#!/bin/bash
args=( $args_str )
EOF
...beyond which, anything inside the script being created would want to expand it as an array:
run_something "${args[#]}"
See BashFAQ #50 for rationale and details.

Answer 3

Besides using consistent case ($app is different from $APP), you may want to enclose your variable names within brackets - you may get issues if you use spaces in between your variables values otherwise, and it's considered a good practice. For example:
args="--emperor ${APPCONF}/test/${APP}.ini"
That way, $APPCONF does not get confused with ${APP}CONF also. I hope this helps!

Answer 4

I'm not sure to understand your question. I suppose that you would like to end with a file
/etc/init.d/test
containing the text:
#!/bin/bash
args="--emperor $APPCONF/test/testing.ini"
if so your script should be:
app="testing"
cat <<EOF >/etc/init.d/test
#!/bin/bash
args="--emperor \$APPCONF/test/$app.ini"
EOF