Re: [PATCH] test: Add unary operator -E: test that a file is an empty directory

[Mattias Andrée]

On Wed, 6 Apr 2016 21:57:11 +0200
Mattias Andrée <address@hidden> wrote:

> On Wed, 6 Apr 2016 15:36:29 -0400
> Assaf Gordon <address@hidden> wrote:
> 
> > 
> > As a temporary work-around, the following seems portable
> > across some OSes (gnu/linux,*BSD) and can be used as a
> > shell function (but '-mindepth' is not in POSIX
> > standard):
> > 
> > dirempty() {
> >   test -d "$1" \
> >      && test -z "$( { find "$1" -mindepth 1 2>/dev/null

Of course, you need -- too.

> > || echo failed ; } | head -n1)" }
> > 
> > usage is:
> > 
> > dirempty DIRNAME && echo empty || echo
> > not-empty-or-error  
> 
> It is too complicated and you need to use find "$1/",
> not find "$1". But you can use:
> 
> test -d "$1" && python - "$1" <<EOF
> import os, sys
> sys.exit(1 if len(os.listdir(sys.argv[1])) else 0)
> EOF
> 
> or
> 
> test -d "$1" && test -z "$(ls -A -- "$1/")"


We have now demonstrated that attempts to
implement this functionally in shell script
without -E is prone to errors in addition
to being messy.

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