Re: Why regex doesn't work in while loop's condition?
On 9/6/19 5:27 PM, Theo de Raadt wrote: Andreas Kusalananda Kähäri wrote: On Fri, Sep 06, 2019 at 02:38:18PM -0600, Theo de Raadt wrote: Christian Weisgerber wrote: On 2019-09-06, Andreas Kusalananda Kähäri wrote: read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done The shells in the OpenBSD base system do not support matching regular expressions with that syntax. You may have been thinking of bash, Just to head off crazy rumors: bash doesn't either. Doesn't bash perform this task by invisibly calling out to perl? You're thinking of zsh. No I'm thinking it is all crazy. CRAZY=true [ is not [[ man ksh [[ expression ]] Similar to the test and [ ... ] commands (described later), with the following exceptions: ... The second operand of the ‘!=’ and ‘=’ expressions are patterns (e.g. the comparison [[ foobar = f*r ]] succeeds). X=a if [[ "$X" == [abc] ]] ; then echo yes ; fi prints yes ksh is in base and is often a user's login shell
Re: Why regex doesn't work in while loop's condition?
Andreas Kusalananda Kähäri wrote: > On Fri, Sep 06, 2019 at 02:38:18PM -0600, Theo de Raadt wrote: > > Christian Weisgerber wrote: > > > > > On 2019-09-06, Andreas Kusalananda Kähäri wrote: > > > > > > >> read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > > > > > > > The shells in the OpenBSD base system do not support matching regular > > > > expressions with that syntax. You may have been thinking of bash, > > > > > > Just to head off crazy rumors: bash doesn't either. > > > > Doesn't bash perform this task by invisibly calling out to perl? > > You're thinking of zsh. No I'm thinking it is all crazy.
Re: Why regex doesn't work in while loop's condition?
On Fri, Sep 06, 2019 at 02:38:18PM -0600, Theo de Raadt wrote: > Christian Weisgerber wrote: > > > On 2019-09-06, Andreas Kusalananda Kähäri wrote: > > > > >> read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > > > > > The shells in the OpenBSD base system do not support matching regular > > > expressions with that syntax. You may have been thinking of bash, > > > > Just to head off crazy rumors: bash doesn't either. > > Doesn't bash perform this task by invisibly calling out to perl? You're thinking of zsh.
Re: Why regex doesn't work in while loop's condition?
On Fri, Sep 6, 2019 at 2:40 PM JohnS wrote: > Why next construction doesn't work? > > read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done People have been focusing on the syntax of arguments for test (the left bracket operation), but there's no 'next' here. You are reading x just once and then going into a loop. That's almost certainly not what you want to do. You might want to be doing something like this: while read x; ! echo $x | egrep -q '[abc]'; do echo 'Not a, b or c'; done But, given how non-functional your code example was, and how non-descriptive your surrounding text was, it's kind of hard to tell... That said, good luck, -- Raul
Re: Why regex doesn't work in while loop's condition?
Christian Weisgerber wrote: > On 2019-09-06, Andreas Kusalananda Kähäri wrote: > > >> read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > > > The shells in the OpenBSD base system do not support matching regular > > expressions with that syntax. You may have been thinking of bash, > > Just to head off crazy rumors: bash doesn't either. Doesn't bash perform this task by invisibly calling out to perl?
Re: Why regex doesn't work in while loop's condition?
On 2019-09-06, Andreas Kusalananda Kähäri wrote: >> read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > The shells in the OpenBSD base system do not support matching regular > expressions with that syntax. You may have been thinking of bash, Just to head off crazy rumors: bash doesn't either. -- Christian "naddy" Weisgerber na...@mips.inka.de
Re: Why regex doesn't work in while loop's condition?
On Fri, Sep 06, 2019 at 08:55:10PM +0200, Andreas Kusalananda Kähäri wrote: > On Fri, Sep 06, 2019 at 11:39:06PM +0500, JohnS wrote: > > Hi, all! > > > > Why next construction doesn't work? > > > > read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > > > I tried many variants but can't make it work. Moreover I don't understand > > WHY it > > doesn't work?! > > > > Thanks! > > The shells in the OpenBSD base system do not support matching regular > expressions with that syntax. You may have been thinking of bash, > > while [[ ! $x =~ [abc] ]]; do ...; done > > Or, in ksh, > > while [[ $x != [abc] ]]; do ...; done > > Here however, [abc] is not a regular expression, but a filename globbing > pattern, and the test will test for equality rather than trying to match > a substring (as would be the case with a regular expression match). "equality" was not quite what I meant. It would test for a match against the whole of $x, as any globbing pattern would do, rather than a substring of $x, as a regular expression would do. I.e., the bash code above tests whether $x *contains* a, b, or c, while the ksh code beneath it tests whether $x *is* a, b or c (and then the result of the test is negated). > > Note that this test requries [[ ... ]] rather than [ ... ]. See the > ksh(1) manual.
Re: Why regex doesn't work in while loop's condition?
On Fri, Sep 06, 2019 at 11:39:06PM +0500, JohnS wrote: > Hi, all! > > Why next construction doesn't work? > > read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done > > I tried many variants but can't make it work. Moreover I don't understand WHY > it > doesn't work?! > > Thanks! The shells in the OpenBSD base system do not support matching regular expressions with that syntax. You may have been thinking of bash, while [[ ! $x =~ [abc] ]]; do ...; done Or, in ksh, while [[ $x != [abc] ]]; do ...; done Here however, [abc] is not a regular expression, but a filename globbing pattern, and the test will test for equality rather than trying to match a substring (as would be the case with a regular expression match). Note that this test requries [[ ... ]] rather than [ ... ]. See the ksh(1) manual.
Why regex doesn't work in while loop's condition?
Hi, all! Why next construction doesn't work? read x; while [ "$x" != [abc] ]; do echo "Not a, b or c"; break; done I tried many variants but can't make it work. Moreover I don't understand WHY it doesn't work?! Thanks!
