change echo to printf and for sfeed_opml_export use a control-character separator

echo is unportable in this way and names containing characters like an option
(-n) or backslash or escape codes (\e, \n, etc) could be messy.

For awk set LC_ALL=C for simple collation.

This makes sfeed_opml_export slower in some shells that don't have printf
builtin though. For example with about 150 feeds in a config file it is a bit
slower on OpenBSD ksh.

time ./sfeed_opml_export | wc -l
     152

    0m00.29s real     0m00.05s user     0m00.20s system

time sfeed_opml_export | wc -l
     152
    0m00.02s real     0m00.00s user     0m00.03s system

1 files changed, 2 insertions, 2 deletions

diff --git a/sfeed_update b/sfeed_update
index 2e54a59..857f537 100755
--- a/sfeed_update
+++ b/sfeed_update
@@ -27,7 +27,7 @@ loadconfig() {
 	if [ -r "${path}" ]; then
 		. "${path}"
 	else
-		echo "Configuration file \"${config}\" cannot be read." >&2
+		printf "Configuration file \"%s\" cannot be read.\n" "${config}" >&2
 		echo "See sfeedrc.example for an example." >&2
 		exit 1
 	fi
@@ -187,7 +187,7 @@ sighandler() {
 }
 
 feeds() {
-	echo "Configuration file \"${config}\" is invalid or does not contain a \"feeds\" function." >&2
+	printf "Configuration file \"%s\" is invalid or does not contain a \"feeds\" function.\n" "${config}" >&2
 	echo "See sfeedrc.example for an example." >&2
 }