On 02/10/2011 12:40 PM, Ralf Wildenhues wrote: > Hello David, > > * Dr. David Kirkby wrote on Thu, Feb 10, 2011 at 07:56:24PM CET: >> I know its considered bad practice to check for an empty string with something like: >> >> if [ "$STR" = "" ] ; then >> >> but what shells do actually break with this, and under what conditions? > > It's not shells that break. It's these kinds of issues: > http://thread.gmane.org/gmane.comp.sysutils.autoconf.general/13706 Ralf pointed out a completely different point from the Solaris /bin/sh syntax issue - that is, that in autoconf scripts, [ and ] are special to m4, and require extra effort to use, so you are more portable using: test "x$STR" = x than you are using: [ "x$STR" = x ] so that m4 doesn't eat the [ and ]. -- Eric Blake eblake@xxxxxxxxxx +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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