Read / Run Environment Variables in a text file

I have an app which runs and re开发者_Python百科ads a text configuration file. This points to several locations of configurations / outputs etc.

Is it possible to use environmental variables inside the text configuration file, rather than hardcoded paths?

LogFilePath=$LOG_FILE_PATH vs LogFilePath=/home/user/logs

When running, the application fails as it cannot expand the Environment Variable. It will be sourced inside the shell before the application is run.

Thanks!

Recently I used this in a (bash) script:

#!/bin/bash
# ...
source config.file
# ...

Where config.file had lines like this:

export ORIG_PATH="${PATH:-.}:/bla/bla"
export SOMESETTING="${SOMEVAR:-"somedefault"},somedata"
...

So the ${parameter:-word} thing worked well for me: use default values, if parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted. (From man bash.)

HTH