Re: Preexec & Printf

Re: Preexec & Printf

[Joshua Symons]

From: Bart Schaefer <schaefer@brasslantern.com>
Date: Thursday, April 25, 2002 8:01 pm
Subject: Re: Preexec & Printf

> On Thu, 25 Apr 2002, Joshua Symons wrote:
> 
> > I have a pretty generic problem, but I can't seem to make my way 
> around> it.
> 
> Re-read the documentation for the preexec function.  In particular:
> 
> > preexec () {
> >         print -Pn "\e]0;%m:%l   -   $* \a"
> > }
> 
> You almost certainly want to refer to $1 rather than to $*.  To 
> remove the
> quotes from the string, you probably want to use ${(z)1}.
> 
> > $ZSH_VERSION = 3.1.9
> 
> You might also want to upgrade to zsh 4.0.4, which has been out for a
> while now.
> 
> 

Same results:
[(ichirou:151:pts/33)~ %] which preexec
preexec () {
        print -Pn "\e]0;%m:%l   -   ${(z)1} \a"
}
[(ichirou:152:pts/33)~ %] printf '^[[32;40mwith quotes\n' 
[32;40mwith quotes
' with quotes
[(ichirou:153:pts/33)~ %] unfunction preexec
[(ichirou:154:pts/33)~ %] printf '^[[32;40mwith quotes\n' 
with quotes

Additionally, I will upgrade to 4.0.4 as well, but I don't believe that
will fix this current issue.

-Josh-

Re: Preexec & Printf

[Bart Schaefer]

On Thu, 25 Apr 2002, Joshua Symons wrote:

> preexec () {
>         print -Pn "\e]0;%m:%l   -   ${(z)1} \a"
> }
> [(ichirou:152:pts/33)~ %] printf '^[[32;40mwith quotes\n'
> [32;40mwith quotes
> ' with quotes

Your specific problem there is that the titlebar escape sequence appears
literally in the command that you're trying to put into the titlebar, so
strange things happen.  I missed that before.  Try ${(qVz)1}.

Re: Preexec & Printf

[Bart Schaefer]

On Thu, 25 Apr 2002, Bart Schaefer wrote:

> Try ${(qVz)1}.

Oops, that's a typo.  I meant ${(QVz)1}.  And even the z probably isn't
necessary, now that I think of it.

Re: Preexec & Printf

[Joshua Symons]

Thx for all the help Geoff & Bart. 
I think I'll just stick with ${(qV)1} for now and change if necessary,
it appears to be working with everything. I'll try switching to ${(qV)2}
if I switch up to 4.0.4. Thx again.

- Josh -

----- Original Message -----
From: Bart Schaefer <schaefer@brasslantern.com>
Date: Thursday, April 25, 2002 9:06 pm
Subject: Re: Preexec & Printf

> On Thu, 25 Apr 2002, Joshua Symons wrote:
> 
> > ${(qV)1} appears to be doing the job in 3.1.9, in 3.0.8 (the version
> > that comes with solaris 9) or 3.0.6 (the version that comes with 
> solaris> 8) it gives a syntax error.
> > However with ${(QV)1} I still get garbage into my shell.
> 
> ${(q)...} adds a level of quoting, and ${(Q)...} removes a level.  Per
> Geoff's message, the (q) is "working" because it quotes the 
> backslashesand so forth, protecting e.g. \a from being emitted as 
> control-G by print.
> 
> However, what you said you wanted was to remove the quotes, so 
> that's why
> I suggested (Q).  That doesn't solve the backslashing problem.
> 
> You could try ${(q)${QV)1}} which would first remove the quotes and 
> thenescape the backslashes, or you can stick with just ${(qV)1}.
> 
> 

Re: Preexec & Printf

[Joshua Symons]

${(qV)1} appears to be doing the job in 3.1.9, in 3.0.8 (the version
that comes with solaris 9) or 3.0.6 (the version that comes with solaris
8) it gives a syntax error.
However with ${(QV)1} I still get garbage into my shell.

[(ichirou:38:pts/22)~ %] which preexec
preexec () {
        print -Pn "\e]0;%m:%l   -   ${(QV)1} \a"
}
[(ichirou:39:pts/22)~ %] printf '^[[32;40mwith
quotes\n'                    
                                                         
  with quotes
[(ichirou:40:pts/22)~ %] 

[(ichirou:40:pts/22)~ %] which preexec
preexec () {
        print -Pn "\e]0;%m:%l   -   ${(qV)1} \a"
}
[(ichirou:41:pts/22)~ %] printf '^[[32;40mwith quotes\n' 
with quotes
[(ichirou:42:pts/22)~ %] 

- Josh -

----- Original Message -----
From: Bart Schaefer <schaefer@brasslantern.com>
Date: Thursday, April 25, 2002 8:45 pm
Subject: Re: Preexec & Printf

> On Thu, 25 Apr 2002, Joshua Symons wrote:
> 
> > I had seen q in the modifier list @
> > http://zsh.sourceforge.net/Doc/Release/zsh_13.html#SEC45
> > I don't see V and z in the modifier list, are they documented?
> 
> Unfortunately that's still the 3.0 -- or perhaps it's 3.1.6 --
> documentation.  You need to read the docs that came with your zsh
> distribution if you want accurate information.
> 
> > Additionally, where is the $* vs $1 documented, since I'm 
> accustomed to
> > $*.
> 
> The 3.1.9 doc (which I just happen to have lying around) says under 
> thepreexec function:
> 
>     ... If the history mechanism is active, the string to be
>     executed is passed as an argument.
> 
> Note "as AN argument", that is, the first and in this case only 
> argument,which is $1.  $* means all the arguments.
> 
> In 4.0.4, this has changed:
> 
>     ... If the history mechanism is active (and the line was not
>     discarded from the history buffer), the string that the user 
> typed     is passed as the first argument, otherwise it is an empty 
> string.     The actual command that will be executed (including 
> expanded     aliases) is passed in two different forms: the second 
> argument is
>     a single-line, size-limited version of the command (with things
>     like function bodies elided); the third argument contains the 
> full     text what what is being executed.
> 
> So in 4.0.4 if you use $* you'll get the command repeated three times,
> which is definitely not what you want.  If you had 4.0.4, you'd 
> probablywant ${(QV)2} or maybe just ${(V)2}.
> 
> 

Re: Preexec & Printf

[Bart Schaefer]

On Thu, 25 Apr 2002, Joshua Symons wrote:

> ${(qV)1} appears to be doing the job in 3.1.9, in 3.0.8 (the version
> that comes with solaris 9) or 3.0.6 (the version that comes with solaris
> 8) it gives a syntax error.
> However with ${(QV)1} I still get garbage into my shell.

${(q)...} adds a level of quoting, and ${(Q)...} removes a level.  Per
Geoff's message, the (q) is "working" because it quotes the backslashes
and so forth, protecting e.g. \a from being emitted as control-G by print.

However, what you said you wanted was to remove the quotes, so that's why
I suggested (Q).  That doesn't solve the backslashing problem.

You could try ${(q)${QV)1}} which would first remove the quotes and then
escape the backslashes, or you can stick with just ${(qV)1}.

Re: Preexec & Printf

[Joshua Symons]

----- Original Message -----
From: Geoff Wing <mason@primenet.com.au>
Date: Thursday, April 25, 2002 8:22 pm
Subject: Re: Preexec & Printf

> Joshua Symons <vmcore@mysun.com> typed:
> : I have a pretty generic problem, but I can't seem to make my way 
> around: it. Here is an example of what is happening:
> 
> : [(ichirou:151:pts/15)~ %] which preexec
> : preexec () {
> :         print -Pn "\e]0;%m:%l   -   $* \a"
> :}
> : [(ichirou:152:pts/15)~ %] printf '^[[32;40mwith quotes\n'
> 
> : For echo, print, and printf, my '' is getting passed (straight 
> quote): into preexec and erroring back out into my shell. I can't 
> seem to get
> : around the quotes that are passed into preexec. This doesn't 
> happen in
> : dtterm for some reason, not sure why. 
> : Any help that could be given would be nice.
> 
> Your problem is different to what you think.  You're using xterm and
> you're expecting it to not print the set of characters sent through 
> thepreexec without consideration of what characters are permissible.
> Obviously you'll have problems if you try to send a BEL (\a) via the

I was actually using the example provided in the xterm title setting
how-to.
Is there a better way to terminate the title?

> normal line because it'll terminate the title-set OSC in the print 
> in the

OSC ?

> preexec().  You'll also have problems with xterm with other non-
> printablecharacters, e.g. ESC, CR, LF - xterm will also use those 
> as terminators
> since they're non-valid.  You'll need to do some more character
> sanitisation first on the string sent via the preexec() print.
> 
> Regards,
> -- 
> Geoff Wing : <gcw@pobox.com>
> Rxvt Stuff : <gcw@rxvt.org>
> Zsh Stuff  : <gcw@zsh.org>
> 

Re: Preexec & Printf

[Geoff Wing]

Joshua Symons <vmcore@mysun.com> typed:
:----- Original Message -----
:From: Geoff Wing <mason@primenet.com.au>
:Date: Thursday, April 25, 2002 8:22 pm
:Subject: Re: Preexec & Printf
:
:> Obviously you'll have problems if you try to send a BEL (\a) via the
:I was actually using the example provided in the xterm title setting
:how-to.
:Is there a better way to terminate the title?

No, I mean, if you try to send a line like:

% echo "hi\athere"

then the BEL will terminate the string sent via the preexec and ``there''
won't end up in the title but will be sent normally onto the display.

:> normal line because it'll terminate the title-set OSC in the print 
:> in the
:OSC ?

OSC=Operating System Command, a terminal (emulator) specific char sequence.
In this case, the  ESC ] 0 . . . ST  sequence to set the title.

:> preexec().  You'll also have problems with xterm with other non-
:> printablecharacters, e.g. ESC, CR, LF - xterm will also use those 
:> as terminators
:> since they're non-valid.  You'll need to do some more character
:> sanitisation first on the string sent via the preexec() print.

AFAIK, you'll still have problems even using the ${(QV)1} sequence because
it gets the line in a raw form - but the print parses it. e.g.

% echo "hi\nthere"

will fail because the V operator won't be effective since \n are just two
characters but the print command in the preexec converts it to one
special non-printable character which terminates the title-set OSC.

Regards,
-- 
Geoff Wing : <gcw@pobox.com>
Rxvt Stuff : <gcw@rxvt.org>
Zsh Stuff  : <gcw@zsh.org>

Re: Preexec & Printf

[Joshua Symons]

I had seen q in the modifier list @
http://zsh.sourceforge.net/Doc/Release/zsh_13.html#SEC45
and had tried that, but it still had the same problem with ${(q)*}, and
I don't see V and z in the modifier list, are they documented?
Additionally, where is the $* vs $1 documented, since I'm accustomed to
$*. Thx btw, it is working correctly now, I really appreciate it.

- Josh -

----- Original Message -----
From: Bart Schaefer <schaefer@brasslantern.com>
Date: Thursday, April 25, 2002 8:16 pm
Subject: Re: Preexec & Printf

> On Thu, 25 Apr 2002, Joshua Symons wrote:
> 
> > preexec () {
> >         print -Pn "\e]0;%m:%l   -   ${(z)1} \a"
> > }
> > [(ichirou:152:pts/33)~ %] printf '^[[32;40mwith quotes\n'
> > [32;40mwith quotes
> > ' with quotes
> 
> Your specific problem there is that the titlebar escape sequence 
> appearsliterally in the command that you're trying to put into the 
> titlebar, so
> strange things happen.  I missed that before.  Try ${(qVz)1}.
> 
> 

Re: Preexec & Printf

[Bart Schaefer]

On Thu, 25 Apr 2002, Joshua Symons wrote:

> I had seen q in the modifier list @
> http://zsh.sourceforge.net/Doc/Release/zsh_13.html#SEC45
> I don't see V and z in the modifier list, are they documented?

Unfortunately that's still the 3.0 -- or perhaps it's 3.1.6 --
documentation.  You need to read the docs that came with your zsh
distribution if you want accurate information.

> Additionally, where is the $* vs $1 documented, since I'm accustomed to
> $*.

The 3.1.9 doc (which I just happen to have lying around) says under the
preexec function:

     ... If the history mechanism is active, the string to be
     executed is passed as an argument.

Note "as AN argument", that is, the first and in this case only argument,
which is $1.  $* means all the arguments.

In 4.0.4, this has changed:

     ... If the history mechanism is active (and the line was not
     discarded from the history buffer), the string that the user typed
     is passed as the first argument, otherwise it is an empty string.
     The actual command that will be executed (including expanded
     aliases) is passed in two different forms: the second argument is
     a single-line, size-limited version of the command (with things
     like function bodies elided); the third argument contains the full
     text what what is being executed.

So in 4.0.4 if you use $* you'll get the command repeated three times,
which is definitely not what you want.  If you had 4.0.4, you'd probably
want ${(QV)2} or maybe just ${(V)2}.

Re: Preexec & Printf

[Oliver Kiddle]

On Thu, Apr 25, 2002 at 06:45:52PM -0700, Bart Schaefer wrote:
> On Thu, 25 Apr 2002, Joshua Symons wrote:
> 
> > I had seen q in the modifier list @
> > http://zsh.sourceforge.net/Doc/Release/zsh_13.html#SEC45
> > I don't see V and z in the modifier list, are they documented?
> 
> Unfortunately that's still the 3.0 -- or perhaps it's 3.1.6 --
> documentation.  You need to read the docs that came with your zsh
> distribution if you want accurate information.

No, it is the 4.0.3 documentation. The reason that V and z are not in
the list of modifiers is that they are parameter expansion flags so
are listed further down in the documentation. #SEC47 or 13.3.1 if
looking on the web page.

As for the original question, I'd have thought it'd be easier to
break up the print statement in preexec to avoid it interpreting
any back-slashes in $1. e.g:
preexec() {
  print -Pn "\e]0;%m:%l - "
  print -rn "${(V)1}"
  print -n "\a"
)

It still needs the V flag for special characters but shouldn't need
any quoting.

Oliver
-- 

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Preexec & Printf

[Joshua Symons]

I have a pretty generic problem, but I can't seem to make my way around
it. Here is an example of what is happening:

[(ichirou:151:pts/15)~ %] which preexec
preexec () {
        print -Pn "\e]0;%m:%l   -   $* \a"
}
[(ichirou:152:pts/15)~ %] printf '^[[32;40mwith quotes\n'
[32;40mwith quotes
' with quotes
[(ichirou:153:pts/15)~ %] unfunction preexec
[(ichirou:154:pts/15)~ %] printf '^[[32;40mwith quotes\n'
with quotes
[(ichirou:155:pts/15)~ %] 

For echo, print, and printf, my '' is getting passed (straight quote)
into preexec and erroring back out into my shell. I can't seem to get
around the quotes that are passed into preexec. This doesn't happen in
dtterm for some reason, not sure why. 
Any help that could be given would be nice.

System Information:
SunOS ichirou 5.8 Generic_108528-12 sun4u sparc SUNW,Ultra-30
$ZSH_VERSION = 3.1.9

thx in advance
-Josh-

Re: Preexec & Printf

[Bart Schaefer]

On Thu, 25 Apr 2002, Joshua Symons wrote:

> I have a pretty generic problem, but I can't seem to make my way around
> it.

Re-read the documentation for the preexec function.  In particular:

> preexec () {
>         print -Pn "\e]0;%m:%l   -   $* \a"
> }

You almost certainly want to refer to $1 rather than to $*.  To remove the
quotes from the string, you probably want to use ${(z)1}.

> $ZSH_VERSION = 3.1.9

You might also want to upgrade to zsh 4.0.4, which has been out for a
while now.

Re: Preexec & Printf

[Geoff Wing]

Joshua Symons <vmcore@mysun.com> typed:
: I have a pretty generic problem, but I can't seem to make my way around
: it. Here is an example of what is happening:
 
: [(ichirou:151:pts/15)~ %] which preexec
: preexec () {
:         print -Pn "\e]0;%m:%l   -   $* \a"
:}
: [(ichirou:152:pts/15)~ %] printf '^[[32;40mwith quotes\n'

: For echo, print, and printf, my '' is getting passed (straight quote)
: into preexec and erroring back out into my shell. I can't seem to get
: around the quotes that are passed into preexec. This doesn't happen in
: dtterm for some reason, not sure why. 
: Any help that could be given would be nice.

Your problem is different to what you think.  You're using xterm and
you're expecting it to not print the set of characters sent through the
preexec without consideration of what characters are permissible.
Obviously you'll have problems if you try to send a BEL (\a) via the
normal line because it'll terminate the title-set OSC in the print in the
preexec().  You'll also have problems with xterm with other non-printable
characters, e.g. ESC, CR, LF - xterm will also use those as terminators
since they're non-valid.  You'll need to do some more character
sanitisation first on the string sent via the preexec() print.
 
Regards,
-- 
Geoff Wing : <gcw@pobox.com>
Rxvt Stuff : <gcw@rxvt.org>
Zsh Stuff  : <gcw@zsh.org>