fold.1posix -b1 <<< "StackOver"
filter for folding lines
-b     Count width in bytes rather than column positions.
Before a command is executed, its input and output may be redirected using a special notation interpreted
by  the  shell.   Redirection  may  also  be used to open and close files for the current shell execution
environment.  The following redirection operators may precede or appear anywhere within a simple  command
or may follow a command.  Redirections are processed in the order they appear, from left to right.

Here Documents
    This type of redirection instructs the shell  to  read  input  from  the  current  source  until  a  line
    containing  only delimiter (with no trailing blanks) is seen.  All of the lines read up to that point are
    then used as the standard input for a command.

    The format of here-documents is:

           <<[-]word
                   here-document
           delimiter

    No parameter expansion, command substitution, arithmetic expansion, or pathname expansion is performed on
    word.   If  any  characters in word are quoted, the delimiter is the result of quote removal on word, and
    the lines in the here-document are not expanded.  If word is unquoted, all lines of the here-document are
    subjected  to  parameter  expansion, command substitution, and arithmetic expansion.  In the latter case,
    the character sequence \<newline> is ignored, and \ must be used to quote the characters \, $, and `.

    If the redirection operator is <<-, then all leading tab characters are stripped from input lines and the
    line  containing  delimiter.  This allows here-documents within shell scripts to be indented in a natural
    fashion.

Here Strings
    A variant of here documents, the format is:

           <<<word

    The word is expanded and supplied to the command on its standard input.
source manpages: fold