Idea for useful utility

[utzoo!decvax!duke!mcnc!ncsu!msdc!dan]

We too had countless problems trying to remember how to run
an 'nroff' document.  We (and our secretaries) have been using
a little shell program called 'runoff' for some time now.
By putting a special comment line at the beginning of an
'nroff' file, you can get it formatted by entering

    runoff <document>

'Runoff' expects the first line of the first file named on
the command line to contain an nroff-style comment as follows:

    .\"  <command line to format the document>

The command can contain 'sh' variable substitutions, since it is
executed by the shell that executes 'runoff'.  Most importantly,
"$1" is replaced by the first argument to 'runoff'.

Most of our things document files begin something like this:

    .\"  tbl $1 | nroff -mm | col


                            Dan Forsyth  (decvax!duke!mcnc!msdc!dan)
                            Medical Systems Development Corp.

======================================
:
# runoff --- format and print a document using its first
#            line as the command

    if CMD=`head -1 $1`; then
        :
    else
        exit
    fi

    if expr 0 = X"$CMD" : '^X\. *\\"' >/dev/null; then
        echo 'First line of document must be .\\" <command>' 1>&2
        exit 1
    fi

    NCMD=`echo "$CMD" | sed 's/^\. *\\\" *//'`

    eval "$NCMD"
======================================