Note that the standard Solaris versions of many commands are substantially faster than their GNU equivalents in the 'C' and multi-byte locales so this advice do

Note that the standard Solaris versions of many commands are substantially faster than their GNU equivalents in the 'C' and multi-byte locales so this advice doesn't necessarily apply. That's part of why Solaris continues to use them in favour of GNU alternatives (although the GNU alternatives are available easily in /usr/gnu/bin).