I'm copying this to groff@xxxxxxx, which I think is a more
appropriate forum for continuation of this discussion.
Ralf Wildenhues wrote:
> Some zsh versions have NULLCMD set to `cat' by default, so the
> command [`>> $REFFILE'] will be equivalent to
>
> cat >> $REFFILE
>
> and thus will read from stdin until EOF. If stdin is connected to
> the terminal, the innocent user will think the program hangs; if it
> points to an open file, that file will end up in $REFFILE.
Given the complete absence of related of bug reports, either:
1) This isn't true (which seems unlikely), or (more likely)
2) No one has attempted to build groff >= 1.19.2, or to use pdfroff,
on any system where /bin/sh is linked to zsh.
Can anyone either confirm or refute the hypothesis that there may be
a zsh related contention in pdfroff?
> Quoting relevant parts of (CVS) autoconf.info:
| Zsh
| To detect whether you are running `zsh', test whether
| `ZSH_VERSION' is set. By default `zsh' is _not_ compatible with
| the Bourne shell: you must execute `emulate sh', and for `zsh'
| versions before 3.1.6-dev-18 you must also set `NULLCMD' to `:'.
| *Note Compatibility: (zsh)Compatibility, for details.
|
| The default Mac OS X `sh' was originally Zsh; it was changed to
| Bash in Mac OS X 10.2.
| `NULLCMD'
| When executing the command `>foo', `zsh' executes `$NULLCMD >foo'
| unless it is operating in Bourne shell compatibility mode and the
| `zsh' version is newer than 3.1.6-dev-18. If are using an older
| `zsh' and forget to set `NULLCMD', your script might be suspended
| waiting for data on its standard input.
So, perhaps the most appropriate action would be to add zsh detection to
pdfroff.sh; e.g. something like:
test x${ZSH_VERSION+"set"} = xset && { emulate sh; NULLCMD=:; }
BTW Ralf, I notice a typo in the above autoconf.info snippet: under the
`NULLCMD' heading, `If are using an older...' should read `If you are...',
i.e. the word `you' is missing.
Regards,
Keith.
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