options for Insert mode completion
'completeslash'	  'csl'	    like 'shellslash' for completion
'concealcursor'	  'cocu'    whether concealable text is hidden in cursor line
'conceallevel'	  'cole'    whether concealable text is shown or hidden
'confirm'	  'cf'	    ask what to do about unsaved/read-only files
'copyindent'	  'ci'	    make 'autoindent' use existing indent structure
'cpoptions'	  'cpo'     flags for Vi-compatible behavior
'cursorbind'	  'crb'     move cursor in window as it moves in other windows
'cursorcolumn'	  'cuc'	    highlight the screen column of the cursor
'cursorline'	  'cul'	    highlight the screen line of the cursor
'cursorlineopt'	  'culopt'  settings for 'cursorline'
'debug'			    set to "msg" to see all error messages
'define'	  'def'     pattern to be used to find a macro definition
'delcombine'	  'deco'    delete combining characters on their own
'dictionary'	  'dict'    list of file names used for keyword completion
'diff'			    use diff mode for the current window
'diffexpr'	  'dex'     expression used to obtain a diff file
'diffopt'	  'dip'     options for using diff mode
'digraph'	  'dg'	    enable the entering of digraphs in Insert mode
'directory'	  'dir'     list of directory names for the swap file
'display'	  'dy'	    list of flags for how to display text
'eadirection'	  'ead'     in which direction 'equalalways' works
'encoding'	  'enc'     encoding used internally
'endoffile'	  'eof'     write CTRL-Z at end of the file
'endofline'	  'eol'     write <EOL> for last line in file
'equalalways'	  'ea'	    windows are automatically made the same size
'equalprg'	  'ep'	    external program to use for "=" command
'errorbells'	  'eb'	    ring the bell for error messages
'errorfile'	  'ef'	    name of the errorfile for the QuickFix mode
'errorformat'	  'efm'     description of the lines in the error file
'eventignore'	  'ei'	    autocommand events that are ignored
'eventignorewin'  'eiw'     autocommand events that are ignored in a window
'expandtab'	  'et'	    use spaces when <Tab> is inserted
'exrc'		  'ex'	    read init files in the current directory
'fileencoding'	  'fenc'    file encoding for multibyte text
'fileencodings'   'fencs'   automatically detected character encodings
'fileformat'	  'ff'	    file format used for file I/O
'fileformats'	  'ffs'     automatically detected values for 'fileformat'
'fileignorecase'  'fic'     ignore case when using file names
'filetype'	  'ft'	    type of file, used for autocommands
'fillchars'	  'fcs'     characters to use for displaying special items
'findfunc'	  'ffu'     function to be called for the |:find| command
'fixendofline'	  'fixeol'  make sure last line in file has <EOL>
'foldclose'	  'fcl'     close a fold when the cursor leaves it
'foldcolumn'	  'fdc'     width of the column used to indicate folds
'foldenable'	  'fen'     set to display all folds open
'foldexpr'	  'fde'     expression used when 'foldmethod' is "expr"
'foldignore'	  'fdi'     ignore lines when 'foldmethod' is "indent"
'foldlevel'	  'fdl'     close folds with a level higher than this
'foldlevelstart'  'fdls'    'foldlevel' when starting to edit a file
'foldmarker'	  'fmr'     markers used when 'foldmethod' is "marker"
'foldmethod'	  'fdm'     folding type
'foldminlines'	  'fml'     minimum number of lines for a fold to be closed
'foldnestmax'	  'fdn'     maximum fold depth
'foldopen'	  'fdo'     for which commands a fold will be opened
'foldtext'	  'fdt'     expression used to display for a closed fold
'formatexpr'	  'fex'     expression used with "gq" command
'formatlistpat'   'flp'     pattern used to recognize a list header
'formatoptions'   'fo'	    how automatic formatting is to be done
'formatprg'	  'fp'	    name of external program used with "gq" command
'fsync'		  'fs'	    whether to invoke fsync() after file write
'gdefault'	  'gd'	    the ":substitute" flag 'g' is default on
'grepformat'	  'gfm'     format of 'grepprg' output
'grepprg'	  'gp'	    program to use