src/pre: Use sed(1) and handle buffering with stdbuf(1)

The while loop and its variables where trimming the string undesirably:

    $ printf '\ta\n b\n' | pre -n out
    out a
    out b

Previously, pre(1) would buffer its output if it wasn't a terminal, and I didn't
want to add the proprietary -u flag to the sed(1) call.  Now we use stdbuf(1)
instead, and get the same behaviour, besides being much much faster.

1 files changed, 1 insertions, 4 deletions

diff --git a/src/pre b/src/pre
index d593ad2..ec212d1 100755
--- a/src/pre
+++ b/src/pre
@@ -27,7 +27,4 @@ shift $((OPTIND - 1))
 PREFIX="${1:-}"
 eval "$(assert-arg -- "$PREFIX" 'PREFIX')"
 
-# FIXME: using "while" so we avoid GNU sed's buffering
-while read -r line; do
-	printf '%s%s %s\n' "$PREFIX" "$SEP" "$line"
-done
+stdbuf -oL sed "s/^/$PREFIX$SEP /"