envsubst

This is a simple Docker image that provides the envsubst executable which can be used when expanding environment variables in strings or files.

Example 1 - string

docker container run --rm -it -e var=value bhgedigital/envsubst sh -c "echo This container has \$var | envsubst"

output:

This container has value

Example 2 - file

docker container run --rm -it -e var=value -v $(pwd):/wd bhgedigital/envsubst sh -c "envsubst < /wd/file.txt > file-subst.txt" && cat file-subst.txt

output:

This container has value