Originally Posted by geekmaster
So, in the case of the kindles, using the "[[" keyword instead of the "[" implicit command may well save a process fork (another instance of busybox), but if busybox is already cached, either way should be reasonable fast (you are running interpreted scripting code after all...)
Which is also why the "[[" is found to work across all kindles - they are all Busybox which supports that syntax since about the same time (2002) Bash adopted it from ksh88.
The problem in this thread came about from off-kindle builds using something other than Bash (specifically here, sh is linked to dash rather than bash).
Developers here just need to know that sometimes they have to populate a chroot or linux-vserver instance with the things a development script expects. (I.E: Not everything "sh" will work under "dash" and not everything Bash-3 will work under Bash-4.)
Hmm... Where did I put my Linux Poker link?