awk vs echo

[Chris L. Fouts]

In message <9102111145.aa01900 at VGR.BRL.MIL>; "Peter Jaspers-Fayer" writes:
> I guess that even after a year of trying, I do not understand the way
> the shell (csh) passes things to it's children, viz:
> 
> This is an excerpt from a longer awk command, and I'm stuck:
> 
> This works
>            awk '{ print "'$user': " $0}'
> as does
>            awk '{ print "'`hostname`': " $0}'
> But not
>            awk '{ print "'`date`': " $0}'     (Spaces(?) Colons(?))
> Even tho
>           echo '{ print "'`date`': " $0}'     works OK, and if I CUT&PASTE
> the result of the echo into another awk '', something like:
> 
>            awk '{ print "Mon Feb 11 11:35:32 EST 1991: " $0}'    IT WORKS!
> 
> Why are the last and 2nd-last awks different?  Anyone please?


The first awk winds up as

	awk '{ print "'Mon Feb 11 11:35:32 EST 1991': " $0}'

which has the awk program spread across multiple arguments as highlighted
below:

	awk '{ print "'Mon Feb 11 11:35:32 EST 1991': " $0}'
            ^^^^^^^^^^^^^^ ^^^ ^^ ^^^^^^^^ ^^^ ^^^^^^^^^^^^^  = 6 args

whereas

	awk '{ print "Mon Feb 11 11:35:32 EST 1991: " $0}'

has the awk program in only 1 argument.

To accomplish what you want (get ready for yet more quotes), try:

	awk '{ print "'"`date`"': " $0}'
                       ^      ^
		       |      |
		       +------+----These quotes prevent the spaces in the
				   date output from splitting up the
				   argument.


My head starts hurting if I look at this too long....

-- 

Chris L. Fouts
Email: dprclf at phobos
Ext: 3850

"Fate is the path of least action."
                             -- Kim Stanley Robinson in "A Short, Sharp Knock"

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