add help message

[peccu]

add commands for receiving a directory in /help message

[nwtgck]

Thanks. I have not known zipped data is unziped by tar xf -.
I'd like to find the tar specification.

edit: I found the description as follows in macOS man.

...
DESCRIPTION
     tar creates and manipulates streaming archive files.  This implementation can extract from tar, pax, cpio, zip, jar, ar, xar,
     rpm, 7-zip, and ISO 9660 cdrom images and can create tar, pax, cpio, ar, zip, 7-zip, and shar archives.
...

edit: tar in Ubuntu 20.04 does not support unzipping by tar.

 tar xf my.zip 
tar: This does not look like a tar archive
tar: Exiting with failure status due to previous errors

[peccu]

Thank you for your review.

• I updated the option for tar command. I missed the x option for it.
• I changed the command from tar to unzip for zip version.
  • unzip in macOS and ubuntu 22.04 doesn't supports stdin, so I created temporary file.
  • from unzip manpage

  Archives read from standard input are not yet supported, except with funzip (and then only the first member of the archive can be extracted).
  

• I tested both zip and tar version in macOS (Catalina, 10.15.7; sorry for old version) and Ubuntu 22.04 (in docker container with zip/unzip installed)