Suppressing failed glob patterns

Suppressing failed glob patterns

[Thorsten Kampe]

Hi,

I like the default in zsh for failed glob patterns (which errors when no 
file matches the pattern). 

For example:
% rm file1.* file2.*                                                          
zsh: no matches found: file1.*

zsh never executes rm (which is fine). Additionially I would like to get 
rid of the error message in a script. Unfortunately redirecting stderr 
does not work (because rm is never executed). Is there a way to keep the 
default and to suppress the error?!

Thorsten

Re: Suppressing failed glob patterns

[Frank Terbeck]

Thorsten Kampe <thorsten@thorstenkampe.de>:
> I like the default in zsh for failed glob patterns (which errors when no 
> file matches the pattern). 
> 
> For example:
> % rm file1.* file2.*                                                          
> zsh: no matches found: file1.*
> 
> zsh never executes rm (which is fine). Additionially I would like to get 
> rid of the error message in a script. Unfortunately redirecting stderr 
> does not work (because rm is never executed). Is there a way to keep the 
> default and to suppress the error?!

Check these settings: <http://zshwiki.org/home/options/expn>

And also see what the difference between

  % echo non-existing-file.*
and
  % echo non-existing-file.*(N)

is.

That's documented in 'man zshexpn' and a list of available modifiers
and flags is also in <http://www.bash2zsh.com/zsh_refcard/refcard.pdf>.

Regards, Frank

-- 
In protocol design, perfection has been reached not when there is
nothing left to add, but when there is nothing left to take away.
                                                  -- RFC 1925

Re: Suppressing failed glob patterns

[N.J. Mann]

In message <gh9g43$rt5$1@ger.gmane.org>,
	Thorsten Kampe (thorsten@thorstenkampe.de) wrote:
> 
> I like the default in zsh for failed glob patterns (which errors when no 
> file matches the pattern). 
> 
> For example:
> % rm file1.* file2.*                                                          
> zsh: no matches found: file1.*
> 
> zsh never executes rm (which is fine). Additionially I would like to get 
> rid of the error message in a script. Unfortunately redirecting stderr 
> does not work (because rm is never executed). Is there a way to keep the 
> default and to suppress the error?!

The answer is to use rm -f in your scripts.


Cheers,
       Nick.
-- 

Re: Suppressing failed glob patterns

[Michael Hernandez]

On Dec 4, 2008, at 4:04 PM, Frank Terbeck wrote:

> Thorsten Kampe <thorsten@thorstenkampe.de>:
>> I like the default in zsh for failed glob patterns (which errors  
>> when no
>> file matches the pattern).
>>
>> For example:
>> % rm file1.* file2.*
>> zsh: no matches found: file1.*
>>
>> zsh never executes rm (which is fine). Additionially I would like  
>> to get
>> rid of the error message in a script. Unfortunately redirecting  
>> stderr
>> does not work (because rm is never executed). Is there a way to  
>> keep the
>> default and to suppress the error?!
>
> Check these settings: <http://zshwiki.org/home/options/expn>
>
> And also see what the difference between
>
>  % echo non-existing-file.*
> and
>  % echo non-existing-file.*(N)
>
> is.
>
> That's documented in 'man zshexpn' and a list of available modifiers
> and flags is also in <http://www.bash2zsh.com/zsh_refcard/ 
> refcard.pdf>.
>

You could use setopt no_nomatch and then rm would run, you'd get this:

% rm nowayjose*
rm: nowayhoe*: No such file or directory

Then you could redirect STDERR:
% rm nowayhoe* 2> /dev/null

[no error]

--Mike H

Re: Suppressing failed glob patterns

[Michael Hernandez]

On Dec 4, 2008, at 4:13 PM, N.J. Mann wrote:

> In message <gh9g43$rt5$1@ger.gmane.org>,
> 	Thorsten Kampe (thorsten@thorstenkampe.de) wrote:
>>
>> I like the default in zsh for failed glob patterns (which errors  
>> when no
>> file matches the pattern).
>>
>> For example:
>> % rm file1.* file2.*
>> zsh: no matches found: file1.*
>>
>> zsh never executes rm (which is fine). Additionially I would like  
>> to get
>> rid of the error message in a script. Unfortunately redirecting  
>> stderr
>> does not work (because rm is never executed). Is there a way to  
>> keep the
>> default and to suppress the error?!
>
> The answer is to use rm -f in your scripts.
>

Actually unless the no_nomatch option is set, rm -f non-existent-file*  
will still cause zsh to tell you there's no match. Although with  
no_nomatch set you will not need to redirect STDERR to suppress the  
error that rm would give you.

--Mike H

Re: Suppressing failed glob patterns

[Frank Terbeck]

N.J. Mann <njm@njm.me.uk>:
> 	Thorsten Kampe (thorsten@thorstenkampe.de) wrote:
> > For example:
> > % rm file1.* file2.*                                                          
> > zsh: no matches found: file1.*
[...]
> 
> The answer is to use rm -f in your scripts.

No it's not. Try it. With zsh's defaults.

Regards, Frank

-- 
In protocol design, perfection has been reached not when there is
nothing left to add, but when there is nothing left to take away.
                                                  -- RFC 1925

Re: Suppressing failed glob patterns

[Thorsten Kampe]

* Frank Terbeck (Thu, 4 Dec 2008 22:04:41 +0100)> 
> Thorsten Kampe <thorsten@thorstenkampe.de>:
> > I like the default in zsh for failed glob patterns (which errors when no 
> > file matches the pattern). 
> > 
> > For example:
> > % rm file1.* file2.*                                                          
> > zsh: no matches found: file1.*
> > 
> > zsh never executes rm (which is fine). Additionially I would like to get 
> > rid of the error message in a script. Unfortunately redirecting stderr 
> > does not work (because rm is never executed). Is there a way to keep the 
> > default and to suppress the error?!
> 
> Check these settings: <http://zshwiki.org/home/options/expn>
> 
> And also see what the difference between
> 
>   % echo non-existing-file.*
> and
>   % echo non-existing-file.*(N)
> 
> is.
> 
> That's documented in 'man zshexpn' and a list of available modifiers
> and flags is also in <http://www.bash2zsh.com/zsh_refcard/refcard.pdf>.

Yes, I know about that. And that's what I've been using until now. But 
it's also exactly what I not what. I don't what to give the command an 
empty pattern. Compare:

% rm non-existing-file.*
zsh: no matches found: non-existing-file.*

% rm non-existing-file.*(N)
rm: missing operand
Try `rm --help' for more information.

I just want rm not to be executed (like it's the default) but without 
the error (which is fine when I do it interactively but not in a 
script).

Thorsten

Re: Suppressing failed glob patterns

[Thorsten Kampe]

* N.J. Mann (Thu, 4 Dec 2008 21:13:15 +0000)> 
> In message <gh9g43$rt5$1@ger.gmane.org>,
> 	Thorsten Kampe (thorsten@thorstenkampe.de) wrote:
> > 
> > I like the default in zsh for failed glob patterns (which errors when no 
> > file matches the pattern). 
> > 
> > For example:
> > % rm file1.* file2.*                                                          
> > zsh: no matches found: file1.*
> > 
> > zsh never executes rm (which is fine). Additionially I would like to get 
> > rid of the error message in a script. Unfortunately redirecting stderr 
> > does not work (because rm is never executed). Is there a way to keep the 
> > default and to suppress the error?!
> 
> The answer is to use rm -f in your scripts.

rm was of course only an example. You can substitute ls or print or 
whatever to see what I mean.

Thorsten

Re: Suppressing failed glob patterns

[Michael Hernandez]

On Dec 4, 2008, at 3:55 PM, Thorsten Kampe wrote:

> Hi,
>
> I like the default in zsh for failed glob patterns (which errors  
> when no
> file matches the pattern).
>
> For example:
> % rm file1.* file2.*
> zsh: no matches found: file1.*
>
> zsh never executes rm (which is fine). Additionially I would like to  
> get
> rid of the error message in a script. Unfortunately redirecting stderr
> does not work (because rm is never executed). Is there a way to keep  
> the
> default and to suppress the error?!
>
> Thorsten
>


I replied but didn't read carefully enough the first time, I see you  
want to keep your default value, so maybe you don't want to setopt  
no_nomatch. If this is the case you could start the function that  
calls the rm command with:

setopt local_options no_nomatch

which will set the option for the duration of the function call but  
return to the default when it's done. This way you have the benefits  
of the option being set for the function without changing your default  
shell behavior.

--Mike H

Re: Suppressing failed glob patterns

[Bart Schaefer]

On Thu, Dec 4, 2008 at 1:24 PM, Thorsten Kampe
<thorsten@thorstenkampe.de> wrote:
> I just want rm not to be executed (like it's the default) but without
> the error (which is fine when I do it interactively but not in a
> script).

Wrapping it in braces should do it:

{ rm non-existing-file.* } 2>/dev/null

Re: Suppressing failed glob patterns

[Frank Terbeck]

Thorsten Kampe <thorsten@thorstenkampe.de>:
> * Frank Terbeck (Thu, 4 Dec 2008 22:04:41 +0100)> 
> > Thorsten Kampe <thorsten@thorstenkampe.de>:
> > > For example:
> > > % rm file1.* file2.*                                                          
> > > zsh: no matches found: file1.*
> > > 
> > > zsh never executes rm (which is fine). Additionially I would like to get 
> > > rid of the error message in a script. Unfortunately redirecting stderr 
> > > does not work (because rm is never executed). Is there a way to keep the 
> > > default and to suppress the error?!
> > 
[...]
> empty pattern. Compare:
> 
> % rm non-existing-file.*
> zsh: no matches found: non-existing-file.*
> 
> % rm non-existing-file.*(N)
> rm: missing operand
> Try `rm --help' for more information.
> 
> I just want rm not to be executed (like it's the default) but without 
> the error (which is fine when I do it interactively but not in a 
> script).

AFAIK, there's no way to do that with a simple option. See the link to
zshwiki.org about that, too. You'd have to check for yourself if a
file matches your pattern and then conditionally run rm.

In that case, just do add -f to rm's options. That'll be a lot
simpler.

Regards, Frank

-- 
In protocol design, perfection has been reached not when there is
nothing left to add, but when there is nothing left to take away.
                                                  -- RFC 1925

Re: Suppressing failed glob patterns

[Benjamin R. Haskell]

On Thu, 4 Dec 2008, Thorsten Kampe wrote:

> Yes, I know about that. And that's what I've been using until now. But 
> it's also exactly what I not what. I don't what to give the command an 
> empty pattern. Compare:
>
> % rm non-existing-file.*
> zsh: no matches found: non-existing-file.*
>
> % rm non-existing-file.*(N)
> rm: missing operand
> Try `rm --help' for more information.
>
> I just want rm not to be executed (like it's the default) but without
> the error (which is fine when I do it interactively but not in a
> script).
>
> Thorsten


You want both of the things suggested in this thread ('-f' and '(N)'):

# original problem
$ rm non-existing-file.*
zsh: no matches found: non-existing-file.*

# '-f' doesn't solve 'no matches'
$ rm -f non-existing-file.*
zsh: no matches found: non-existing-file.*

# '(N)' doesn't solve the 'missing operand'
$ rm non-existing-file.*(N)
rm: missing operand
Try `rm --help' for more information.

# '(N)' solves one, '-f' solves the other
$ rm -f non-existing-file.*(N)
$


Best,
Ben

Re: Suppressing failed glob patterns

[Thorsten Kampe]

* Michael Hernandez (Thu, 4 Dec 2008 16:26:37 -0500)> 
> On Dec 4, 2008, at 3:55 PM, Thorsten Kampe wrote:
> > I like the default in zsh for failed glob patterns (which errors  
> > when no
> > file matches the pattern).
> >
> > For example:
> > % rm file1.* file2.*
> > zsh: no matches found: file1.*
> >
> > zsh never executes rm (which is fine). Additionially I would like to  
> > get
> > rid of the error message in a script. Unfortunately redirecting stderr
> > does not work (because rm is never executed). Is there a way to keep  
> > the
> > default and to suppress the error?!
> >
> > Thorsten
> >
> 
> 
> I replied but didn't read carefully enough the first time, I see you  
> want to keep your default value, so maybe you don't want to setopt  
> no_nomatch. If this is the case you could start the function that  
> calls the rm command with:
> 
> setopt local_options no_nomatch

Yes, that's what I've been using until now. The problem is that I don't 
know what a program that expects an argument will do if it receives no 
argument. It might simply print help or await input from stdin. So the 
default is for me exactly the best. Only the zsh's error is a kind of a 
cosmetic problem in script (while interactively it's of course what I 
want).

Thorsten

Re: Suppressing failed glob patterns

[Thorsten Kampe]

* Bart Schaefer (Thu, 4 Dec 2008 13:27:50 -0800)> 
> On Thu, Dec 4, 2008 at 1:24 PM, Thorsten Kampe
> <thorsten@thorstenkampe.de> wrote:
> > I just want rm not to be executed (like it's the default) but without
> > the error (which is fine when I do it interactively but not in a
> > script).
> 
> Wrapping it in braces should do it:
> 
> { rm non-existing-file.* } 2>/dev/null

Right. Surprisingly (for me) it does. Thanks.

Thorsten

Re: Suppressing failed glob patterns

[Stephane Chazelas]

On Thu, Dec 04, 2008 at 09:55:37PM +0100, Thorsten Kampe wrote:
[...]
> I like the default in zsh for failed glob patterns (which errors when no 
> file matches the pattern). 
> 
> For example:
> % rm file1.* file2.*                                                          
> zsh: no matches found: file1.*
> 
> zsh never executes rm (which is fine). Additionially I would like to get 
> rid of the error message in a script. Unfortunately redirecting stderr 
> does not work (because rm is never executed). Is there a way to keep the 
> default and to suppress the error?!
[...]

{rm file1.* file2.*} 2> /dev/null

-- 
Stéphane

Re: Suppressing failed glob patterns

[Stephane Chazelas]

On Thu, Dec 04, 2008 at 04:30:58PM -0500, Benjamin R. Haskell wrote:
> On Thu, 4 Dec 2008, Thorsten Kampe wrote:
>
>> Yes, I know about that. And that's what I've been using until now. But 
>> it's also exactly what I not what. I don't what to give the command an 
>> empty pattern. Compare:
>>
>> % rm non-existing-file.*
>> zsh: no matches found: non-existing-file.*
>>
>> % rm non-existing-file.*(N)
>> rm: missing operand
>> Try `rm --help' for more information.
>>
>> I just want rm not to be executed (like it's the default) but without
>> the error (which is fine when I do it interactively but not in a
>> script).
>>
>> Thorsten
>
>
> You want both of the things suggested in this thread ('-f' and '(N)'):
>
> # original problem
> $ rm non-existing-file.*
> zsh: no matches found: non-existing-file.*
>
> # '-f' doesn't solve 'no matches'
> $ rm -f non-existing-file.*
> zsh: no matches found: non-existing-file.*
>
> # '(N)' doesn't solve the 'missing operand'
> $ rm non-existing-file.*(N)
> rm: missing operand
> Try `rm --help' for more information.
>
> # '(N)' solves one, '-f' solves the other
> $ rm -f non-existing-file.*(N)
> $
[...]

But

rm -f file1.*(N) file2.*(N)

would silently remove file1.xxx while there's no file2.* file
which the OP didn't want (he wanted rm not to be run if any one
pattern doesn't match any file).

-- 
Stéphane

Re: Suppressing failed glob patterns

[Thorsten Kampe]

* Stephane Chazelas (Thu, 4 Dec 2008 21:36:17 +0000)> 
> On Thu, Dec 04, 2008 at 09:55:37PM +0100, Thorsten Kampe wrote:
> [...]
> > I like the default in zsh for failed glob patterns (which errors when no 
> > file matches the pattern). 
> > 
> > For example:
> > % rm file1.* file2.*                                                          
> > zsh: no matches found: file1.*
> > 
> > zsh never executes rm (which is fine). Additionially I would like to get 
> > rid of the error message in a script. Unfortunately redirecting stderr 
> > does not work (because rm is never executed). Is there a way to keep the 
> > default and to suppress the error?!
> [...]
> 
> {rm file1.* file2.*} 2> /dev/null

Thanks, also :)

Thorsten

Re: Suppressing failed glob patterns

[Michael Hernandez]

On Dec 4, 2008, at 4:32 PM, Thorsten Kampe wrote:

> * Michael Hernandez (Thu, 4 Dec 2008 16:26:37 -0500)>
>> On Dec 4, 2008, at 3:55 PM, Thorsten Kampe wrote:
>>> I like the default in zsh for failed glob patterns (which errors
>>> when no
>>> file matches the pattern).
>>>
>>> For example:
>>> % rm file1.* file2.*
>>> zsh: no matches found: file1.*
>>>
>>> zsh never executes rm (which is fine). Additionially I would like to
>>> get
>>> rid of the error message in a script. Unfortunately redirecting  
>>> stderr
>>> does not work (because rm is never executed). Is there a way to keep
>>> the
>>> default and to suppress the error?!
>>>
>>> Thorsten
>>>
>>
>>
>> I replied but didn't read carefully enough the first time, I see you
>> want to keep your default value, so maybe you don't want to setopt
>> no_nomatch. If this is the case you could start the function that
>> calls the rm command with:
>>
>> setopt local_options no_nomatch
>
> Yes, that's what I've been using until now. The problem is that I  
> don't
> know what a program that expects an argument will do if it receives no
> argument. It might simply print help or await input from stdin. So the
> default is for me exactly the best. Only the zsh's error is a kind  
> of a
> cosmetic problem in script (while interactively it's of course what I
> want).
>
> Thorsten
>

Actually with no_nomatch set an argument is passed. See below:

setopt no_nomatch
rm fake*
rm: fake*: No such file or directory

See, the argument is passed but the * is passed as a literal * not as  
a pattern.

--Mike H

Re: Suppressing failed glob patterns

[Benjamin R. Haskell]

[Sorry -- responded from the wrong address, and didn't get the mailing 
list notice until today]

On Thu, 4 Dec 2008, Thorsten Kampe wrote:

> rm was of course only an example. You can substitute ls or print or 
> whatever to see what I mean.
>
> Thorsten

You might also be interested in the '--no-run-if-empty' flag to 'xargs'.

pros: doesn't depend on nullglob setting, shell portability (e.g. 
non-Zsh), more general
cons: more complex, depends on 'find' and 'xargs'

(Probably not the best solution, but it can't hurt to know.)

Examples:

find -maxdepth 1 -name 'might-not-exist.*' -print0 \
| xargs -iZ -0 --no-run-if-empty rm Z

find -maxdepth 1 -name 'might-not-exist.*' -print0 \
| xargs -iZ -0 --no-run-if-empty ls -l Z

find -maxdepth 1 -name 'might-not-exist.*' -print0 \
| xargs -iZ -0 --no-run-if-empty echo Z


# Unrelated to the current problem, but somewhere I found it useful:
# renice Audacious if it's running
pgrep audacious | xargs --no-run-if-empty sudo renice -5

Best,
Ben