On Wed, Aug 23, 2017 at 03:23:50PM -0400, Greg Wooledge wrote:
> On Wed, Aug 23, 2017 at 01:16:56PM -0600, Aaron Toponce wrote:
> > Three POSIX-compliant shell functions that rely on no extra utilities
> > shuff () {
> > if [ $(command -v shuf) ]
>
> Needs quotes.
Good catch.
> > shuffle -f /dev/stdin -p "$1"
>
> /dev/stdin is not POSIX-compliant.
Interesting. I was not aware of that.
> > else
> > awk 'BEGIN{
> > "od -tu4 -N4 -A n /dev/urandom" | getline
>
> /dev/urandom is not POSIX-compliant. Then again, I don't believe there
> is *any* POSIX-compliant source of randomness available to shell scripts
> other than awk's srand and rand.
>
> Emulating /dev/urandom in awk is left as an exercise. ;-)
>
> > [ $(uname) = "SunOS" ] && FILE="/usr/dict/words" ||
> > FILE="/usr/share/dict/words"
>
> It'd be better to list all the possible places the dict file may exist,
> and iterate through them until you find it, regardless of uname.
Agreed. I tested this on the BSDs, GNU/Linux, and Solaris/OmniOS/SmartOS. I
don't have access to HP-UX, IBM AIX, True64, and some of the other Unices. Is
Plan9 still a thing?
> Also, don't use all-caps shell variable names. All-caps names are
> reserved for special internal variables, and environment variables.
I've gone back and forth on this. I'd be interested to see a standard
specification on this, if such exists. It seems convention that uppercase is
used more frequently for shell variables than lowercase. I've tended to lean on
uppercase more frequently as a result. Just so long as it doesn't clash with
existing variables, I don't see the reason not to.
--
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