Inline manual in shell scripts

script-with-inline-documentation.sh

#! /bin/sh

__check_for_help()
{
    set +u    # disable 'nounset' because positional parameters may be unset

    # check $0 against the file name because of scripts sourcing shell libraries
    # with inline documentation
    test $(basename $0) = 'libUMI.sh' -a \( '--help' = "$1" -o '-h' = "$1" \) \
        && exec sed -n '/^#--/ {s/^#--//; p}' $0 | less -+S -FRX && exit 1
}
__check_for_help "$@"

#--
#--NAME
#--    blurb
#--
#--SYNOPSIS
#--    ./blurb --help
#--    ./blurb -h
#--
#EOF

This Gist demonstrates how to include documentation into shell scripts.