which finds binary that is not found in sh
~ # which arm-none-eabi-gcc
/usr/local/gcc-arm-none-eabi-4_8-2014q3/bin/arm-none-eabi-gcc
~ # arm-none-eabi-gcc
/bin/sh: arm-none-eabi-gcc: not found
~ #
(from redmine: issue id 7544, created on 2017-07-17)