I am new to unix and would appreciate if someone could help.

I have an environment variable SourceFilePath=/db1/Src/test set on the unix server.

I want to expand this SHELL variable in a file using any command sed, awk etc

File contents is as follows:

var=$SourceFilePath/file.txt

The command should create a new file by subsituting the environment variable with the actual value.

The output should look like this.

var=/db1/Src/test/file.txt