awk arguments

[Roger Rohrbach]

mayne at VSSERV.SCRI.FSU.EDU (William (Bill) Mayne) writes:

> I have never been able to get the command line assignment of 
> awk variables to work.

    I tried this on SunOS, too.  It seems like a bug.


> The practical problem this raises is how to communicate an
> argument value or a value calculated by a script file into
> an awk program embedded in a script file.

    This is simply a matter of escaping from the quoted awk program
to collect the values of shell variables.  It can be done anywhere in
your awk program, but I tend to assign them all in the BEGIN section:

    awk '

	BEGIN {
	    user = "'$USER'";
	    arg = "'$1'";
	}

	{
	    print user, arg
	}'

will set the awk variables user and arg to the values of the shell
variables $USER and $1, respectively, and then print them for each
awk input record.


> the version actually available on every flavor of unix
> I have seen is much weaker than the full version described by the book.

    Yes, the awk supplied with most Unix systems dates from UNIX Version 7.
The book describes a version you must buy from the AT&T Toolchest!  At
least, you had to do so when the book first came out; now you can get an
implementation of that language free- GNU awk (gawk).  It chokes on my
best work (written in "old awk"), however, so I don't bother with it.

    I am an old awk hand, and prefer the older ("weaker"?) version.  The
addition of functions and all manner of bells and whistles to my beloved
pattern-directed little language disappointed me.  To see how "weak" the
original awk is, see my recent posting of a complete LISP interpreter,
written in that version of awk, to comp.lang.lisp.

Roger Rohrbach                                  sun!wrs!roger    roger at wrs.com
- Eddie sez: ----------------------------------------------- (c) 1986, 1990 -.
|   {o >o                                                                     |
|    \ -) "I was an infinitely hot and dense dot."                            |