neno: Rewrite: easier to understand the redirection.

neno/neno

@@ -34,7 +34,7 @@ No output if file exists:
 
 =head1 AUTHOR
 
-Copyright (C) 2017 Ole Tange,
+Copyright (C) 2017-2020 Ole Tange,
 http://ole.tange.dk and Free Software Foundation, Inc.
 
 
@@ -64,23 +64,21 @@ B<man>
 =cut
 
 _tmp=$(mktemp -d /tmp/no-error.XXXXX)
-true 2>$_tmp/stderr >$_tmp/stdout
-# Save original stdout/stderr
-exec 11>&1 12>&2 
-# Redirect stdout/stderr to tmpfiles
-exec 1>$_tmp/stdout 2>$_tmp/stderr
-# Open the tmpfiles for reading
+true >$_tmp/stdout 2>$_tmp/stderr
+# Open the tmp-files for reading on file descriptor 21+22
 exec 21<$_tmp/stdout 22<$_tmp/stderr
-# Unlink files (but keep them open)
-rm -rf $_tmp
+(
+    # Unlink tmp-files (but keep them open)
+    rm -rf $_tmp
 
-eval "$@"
+    eval "$@"
+) >$_tmp/stdout 2>$_tmp/stderr 
 _error=$?
 if [ $_error == 0 ] ; then
     # skip
     true
 else
-    cat 0<&21 >&11
-    cat 0<&22 >&12
+    cat 0<&21
+    cat 0<&22 >&2
 fi
 exit $_error