$gsf --help
Usage:
  gsf [OPTION...] SUBCOMMAND ARCHIVE...

Help Options:
  -?, --help        Show help options

Application Options:
  -v, --version     Display program version


$ gsf-office-thumbnailer --help
Usage:
  gsf-office-thumbnailer [OPTION...] Options

Help Options:
  -?, --help                Show help options

Application Options:
  -i, --input=filename      Name of file for which to create a thumbnail
  -o, --output=filename     Name of the file to put the thumbnail
  -s, --size=N              Size of thumbnail in pixels; the thumbnail will be at most N*N pixels large

Subcommands
     cat  Output one or more files in archive

     dump Dump one or more files in archive as

     help List subcommands

     list List files in archive

     props
          Archive list of property names

EXAMPLES
     To list the content structure of a Microsoft Excel(TM)  file
     arrays.xls:

     gsf list arrays.xls

     To dump Workbook, an individual data stream in arrays.xls:

     gsf dump arrays.xls Workbook