Docker ADD command

The docker ADD command can be used to copy the files or directories from the Docker host to the image file system. The ADD instruction is similar to the COPY instruction. However, in addition to the functionality supported by the COPY instruction, the ADD instruction can handle the TAR files and the remote URLs. If source is given with TAR files either from file system or from remote URLs, ADD command will not just copy that TAR file but automatically uploads, uncompresses, and puts the resulting folders and files of TAR file at the destination. If you source is a TAR file for a COPY command, COPY command just copy that TAR file to destination, it will not uncompress and extract the files from it.

Docker ADD command Syntax

• <src> can be either file or can be directory.  

• If <dst> not starts with / then it is considered as absolute path. 

• If <dst> starts with / then it is considered as relative path to the work directory. 

• If <dst> ends with / the it is considered as directory. 

• If <dst> does not ends with / the it is considered as file. A file without any extension will be created. 

• <src> not necessary to start with / and always considered as relative to the directory where dockerfile is located. If your docker file is located in C:/docker/test/dockerfile then for the command “COPY sources/config.xml app.xml” config.xml is located from C:/docker/test/sources/config.xml         

sources, /sources, sources/, /sources/ these all are considered to be same sources directory.

• <src> is considered as file only if it has file extension. 

• <src> can have multiple files. You can specify multiple files either directly or through wildcards. When <src> has multiple files then <dst> should be directory. 

• If <src> is tar file specified either form file system or from remote URL, then <dst> should be directory. 

• <src> is directory then <dst> should be directory.