Docker supports Go templates which you can use to manipulate the output format of certain commands and log drivers.

Docker provides a set of basic functions to manipulate template elements. All of these examples use the docker inspect command, but many other CLI commands have a --format flag, and many of the CLI command references include examples of customizing the output format.

[!NOTE]

When using the --format flag, you need observe your shell environment. In a POSIX shell, you can run the following with a single quote:

console $ docker inspect --format '\{\{join .Args " , "}}'

Otherwise, in a Windows shell (for example, PowerShell), you need to use single quotes, but escape the double quotes inside the parameters as follows:

console $ docker inspect --format '\{\{join .Args \" , \"}}'

join#

join concatenates a list of strings to create a single string. It puts a separator between each element in the list.

$ docker inspect --format '\{\{join .Args " , "}}' container

table#

table specifies which fields you want to see its output.

$ docker image list --format "table \{\{\.ID}}\t\{\{\.Repository}}\t\{\{\.Tag}}\t\{\{\.Size}}"

json#

json encodes an element as a json string.

$ docker inspect --format '\{\{json .Mounts}}' container

lower#

lower transforms a string into its lowercase representation.

$ docker inspect --format "\{\{lower .Name}}" container

split#

split slices a string into a list of strings separated by a separator.

$ docker inspect --format '\{\{split .Image ":"}}' container

title#

title capitalizes the first character of a string.

$ docker inspect --format "\{\{title .Name}}" container

upper#

upper transforms a string into its uppercase representation.

$ docker inspect --format "\{\{upper .Name}}" container

println#

println prints each value on a new line.

$ docker inspect --format='\{\{range .NetworkSettings.Networks}}\{\{println .IPAddress}}\{\{end}}' container

Hint#

To find out what data can be printed, show all content as json:

$ docker container ls --format='\{\{json .}}'