Re: Simple "print" in END condition prints last line

[Manuel Collado]

James Kanze escribió:
> Not a serious problem, but a simple "print" in the END condition
> prints the last line, e.g.:
>
>     awk 'BEGIN { printf( "     " ) } ; /^#/ { next } ; { printf( "
> %s", $2 ) } ; END { print }' rebuild.cmds
>
> Where rebuild.cmds is:
>     pagnu002 linux    comp=gcc           arch=i80x86  syst=linux
>     padev001 suncc    comp=suncc         arch=sparc   syst=solaris
>     padev001 sunccstl comp=suncc-stlport arch=sparc   syst=solaris
>     padev001 gcc      comp=gcc           arch=sparc   syst=solaris
>     padev001 v9       comp=suncc         arch=sparcv9 syst=solaris
>     padev001 v9stl    comp=suncc-stlport arch=sparcv9 syst=solaris
>     # pahmg001 linux64  comp=gcc           arch=x86_64  syst=linux
> (no leading spaces) outputs:
>       linux suncc sunccstl gcc v9 v9stl# pahmg001 linux64  comp=gcc
>        arch=x86_64  syst=linux
> instead of the desired:
>       linux suncc sunccstl gcc v9 v9stl
>
> The obvious work-around: replace the ``print'' with ``print
> ""''.  But print without an argument should output $0, and the
> END condition doesn't have a $0.

This is expected behaviour. Quoting the Gawk manual:

-------------------
6.1.4.2 Input/Output from BEGIN and END Rules

...

Traditionally, due largely to implementation issues, $0 and NF were 
undefined inside an END rule. The POSIX standard specifies that NF is 
available in an END rule. It contains the number of fields from the last 
input record. Most probably due to an oversight, the standard does not 
say that $0 is also preserved, although logically one would think that 
it should be. In fact, gawk does preserve the value of $0 for use in END 
rules. Be aware, however, that Unix awk, and possibly other 
implementations, do not.
--------------------

Regards.
--
Manuel Collado - http://lml.ls.fi.upm.es/~mcollado