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Can I use environment variables in my CMD stanza in a Dockerfile?
I want to do something like this:
CMD ["myserver", "--arg=$ARG", "--memcache=$MEMCACHE_11211_TCP_ADDR:$MEMCACHE_11211_TCP_PORT"] Where $MEMCACHE_11211_TCP_* would be set automatically by the inclusion of the --link parameter of my docker run command. And $ARG would be configurable by the user at runtime, maybe by the "-e" parameter?
This doesn't seem to be working for me, it seems to be literally passing through the string "$ARG" for example.
793
To Check if an Environment Variable ExistsSelect Start > All Programs > Accessories > Command Prompt. In the command window that opens, enter echo %VARIABLE%. Replace VARIABLE with the name of the environment variable.
In the Settings window, under Related Settings, click Advanced system settings. On the Advanced tab, click Environment Variables. Click New to create a new environment variable. Click Edit to modify an existing environment variable.
You can open a Command Prompt, type set , and press Enter to display all current environment variables on your PC. You can open PowerShell, type Get-ChildItem Env: , and press Enter to display all current environment variables on your PC.
This answer may be a little late. But environment for CMD is interpreted slightly differently depending on how you write the arguments. If you pass the CMD as a string (not inside an array), it gets launched as a shell instead of exec. See https://docs.docker.com/engine/reference/builder/#cmd.
You may try the CMD without the array syntax to run as a shell:
CMD myserver --arg=$ARG --memcache=$MEMCACHE_11211_TCP_ADDR:$MEMCACHE_11211_TCP_PORT If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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