Unshar normally unpacks its files in the current directory. Use the ``-c'' option to have the program change to a new directory before invoking the shell. If the directory does not exist, it will try to create it. If the directory name starts with a question mark, then unshar will ask for the directory name before doing anything; this is most useful with the environment variable UNSHAREDIR. If the directory name starts with a tilde, then the value of the HOME environment variable is inserted in place of that character. For convenience, the ``-d'' option is a synonym for the ``-c'' option.
Unshar normally complains if the input looks like something other than a shar file. (Among other things, it checks for files that resemble C, and Pascal code). It can be fooled, however, by nonstandard versions of news, notes, etc. The ``-f'' option forces unshar to try unpacking files, even if they look like something else.
Depending on how the program is installed, unshar may or may not try to preserve the header part of file ``foo'' into the name ``foo.hdr'' (if the file is standard input, the name will be ``UNSHAR.HDR''). Using the Using the ``-s'' option forces the program to save the headers, while using the ``-n'' option forces it to discard the headers. The file is appended to, if it already exists, so all headers can be easily saved in one file.