From: Stephane Chazelas <stephane@chazelas.org>
To: zzapper <zsh@rayninfo.co.uk>
Cc: zsh-users@zsh.org
Subject: Re: Can I test if a parameter expansion has worked
Date: Tue, 20 Sep 2022 13:49:01 +0100 [thread overview]
Message-ID: <20220920124901.aucgw4gyvxiz72f2@chazelas.org> (raw)
In-Reply-To: <f93d2561-a8d8-c952-2aeb-8bcf43eef1cb@rayninfo.co.uk>
2022-09-15 08:34:34 +0100, zzapper:
[...]
> f=stuff.jpg;
>
> print ${f/%(#m).[pjg][npi]e#[gf]/_s$MATCH}
>
> stuff_s.jpg # good this is what i want
>
> # now pass 'bad' input
>
> f=stuff.txt;
>
> print ${f/%(#m).[pjg][npi]e#[gf]/_s$MATCH}
> stuff.txt # expansion has obviously left the input unchanged but can I
> test for that???
[...]
You could always do:
unset flag
print -r -- ${f/%(#m).[pjg][npi]e#[gf]/_s$MATCH${flag=}}
if (( $+flag )) echo it did substitute
Note that "print $var" without the -- is a command injection
vulnerability and without -r generally not what you want.
--
Stephane
next prev parent reply other threads:[~2022-09-20 12:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-14 10:03 zzapper
2022-09-14 18:36 ` Bart Schaefer
2022-09-15 0:08 ` Alex Satrapa
2022-09-15 7:34 ` zzapper
2022-09-15 8:24 ` Peter Stephenson
2022-09-15 8:38 ` zzapper
2022-09-15 16:48 ` Bart Schaefer
2022-09-20 7:14 ` david rayner
2022-09-16 0:41 ` Alex Satrapa
2022-09-20 12:49 ` Stephane Chazelas [this message]
2022-09-20 13:25 ` Stephane Chazelas
2022-09-20 13:31 ` Stephane Chazelas
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