Date: Tue, 31 Jan 2017 20:01:43 +0100 From: Polytropon <freebsd@edvax.de> To: byrnejb@harte-lyne.ca Cc: freebsd-questions@freebsd.org Subject: Re: Variable assignment in sh Message-ID: <20170131200143.00c5e5da.freebsd@edvax.de> In-Reply-To: <5f51e2c3bdb8a20c6a7786c2b345c957.squirrel@webmail.harte-lyne.ca> References: <b831bd9e40321e59910ea8913c7a6302.squirrel@webmail.harte-lyne.ca> <20170131161824.a9f1ef46.freebsd@edvax.de> <b553c644fccc211f9658b31cfe65e8a0.squirrel@webmail.harte-lyne.ca> <20170131185103.7f911dfb.freebsd@edvax.de> <5f51e2c3bdb8a20c6a7786c2b345c957.squirrel@webmail.harte-lyne.ca>
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On Tue, 31 Jan 2017 12:56:40 -0500, James B. Byrne wrote: > > On Tue, January 31, 2017 12:51, Polytropon wrote: > > On Tue, 31 Jan 2017 12:11:49 -0500, James B. Byrne via > > freebsd-questions wrote: > >> > >> In any case, I now have set the shell in the root crontab file > >> explicitly to /usr/local/bin/bash in hopes of avoiding this problem > >> in the future. > > > > That _might_ introduce problems in the future when bash is not > > available. My suggestion: Use /bin/sh for scripting except you > > need to rely on a "bash-ism", a feature that bash can provide, > > but sh cannot. However, you can use bash interactively to test > > sh commands, there is "backward compatibility" (bash can be seen > > as a superset of sh). > > > > How would bash become unavailable on this particular system without > someone specifically removing it? A rare occassion, but possible. Let's say in a worst-case scenario, /usr isn't mounted, and you need to stick with what's on /, then bash, which per default is /usr/local/bin/bash, isn't available. However, bash can be linked statically _and_ copied to a location on /, then you won't have that kind of problem. Portability also could be a problem when you try to run something that expects bash on a system where bash isn't installed. Always keep in mind that bash is _not_ part of FreeBSD, while sh is. I know, those are very special cases, and if your goal is not portability and "guaranteed availability", then it won't hit you. I just thought it's worth being mentioned. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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