Causes 7-Zip to read data from stdin (standard input) instead of from disc files.
-si{file_name}
Note: The current version of 7-Zip support reading of archives from stdin only for xz, lzma, tar, gzip and bzip2 archives.
7z a archive.gz -tgzip -siDoc2.txt < Doc.txt
compresses input stream from file Doc.txt to archive.gz archive using Doc2.txt file name.
7z x 7z905.tar.gz -so | 7z x -si -ttar
decompresses tar.gz archive.
a (Add), e (Extract), u (Update), x (Extract with full paths)