The envsubsty converts the specified environment variables in files to their value.
Unlike the classic envsubst, this application might convert complex variables like ${FOO:-${BAR:-value}}
.
envsubsty [-hVwe] [-v 'vars'] [file|directory ...]
Or
cat file.txt | envsubsty [-v 'vars']
Flags:
-V
- Show version.-h
- Show help message.-v 'string'
- Comma or space-separated list of variables to convert.-w
- Write the output to the source file.-e
- Convert empty variables.