make br use bash, and be easier to read

dotfiles/scripts/br

@@ -1,11 +1,21 @@
-#!/bin/sh
+#!/bin/bash
 # Copyright Cédric Picard 2014 -- License WTFPL
 # Inspired by Ranger's -- See https://github.com/hut/ranger
+#
+# Code shuffled around by Leonardo Eugênio 2020
 
 set -e -u
 
+end(){
+    rm -r -- "$(dirname -- "${namebase}")"
+    [ $# -ne 0 ] && echo $@ >&2
+    exit $#
+}
+
 if [ $# -ne 0 ] ; then
-    { for i in "$@" ; do printf "%s\n" "$i" ; done } | "$0"
+    for i in "$@" ; do
+        printf "%s\n" "$i"
+    done  | "$0"
     exit $?
 fi
 
@@ -15,28 +25,23 @@ namebase="$(mktemp -d)/blkrn"
 echo '# Modify filenames without removing any line, quitting aborts' \
     > "${namebase}.2"
 tee -- "${namebase}.1" >> "${namebase}.2"
-exec </dev/tty >/dev/tty \
-    || { echo 'Interactive terminal needed' >&2 ; exit 1; }
+exec </dev/tty >/dev/tty ||
+    end 'Interactive terminal needed'
 
-"$EDITOR" "${namebase}.2"
+"$EDITOR" -- "${namebase}.2"
 sed -i -- '1d' "${namebase}.2"
 
-if [ $(wc -l < "${namebase}.1") -ne $(wc -l < "${namebase}.2") ] ; then
-    rm -r -- "$(dirname -- "${namebase}")"
-    echo "Wrong number of lines" >&2 ; exit 1
-fi
+! diff -- "${namebase}.1" "${namebase}.2" &> /dev/null || end "no changes"
+[ `wc -l < "${namebase}.1"` -eq `wc -l < "${namebase}.2"` ] || end "Wrong number of lines"
 
-(echo '# Please review/modify this script or empty it to do nothing' \
-    ; while read -r l1 <&3 && read -r l2 <&4; do
-        [ "$l1" = "$l2" ] || printf "%s\n%s\n" "$l1" "$l2"
-      done 3<"${namebase}.1" 4<"${namebase}.2" \
-    | sed 's/\([\\"$`]\)/\\\1/g;s/^.*$/"&"/' \
-    | xargs -d"\n" -L2 echo 'mv -i --') \
-    > "${namebase}.sh"
+{
+    echo '# Please review/modify this script or empty it to do nothing'
+    while read -r l1 <&3 && read -r l2 <&4; do
+        [ "$l1" = "$l2" ] || printf "mv -i -- %q %q" "$l1" "$l2"
+    done 3<"${namebase}.1" 4<"${namebase}.2"
+} > "${namebase}.sh"
 
-if [ "$(wc -c < "${namebase}.sh")" -ne 0 ] ; then
-    "$EDITOR" -- "${namebase}.sh"
-    sh -e -- "${namebase}.sh"
-fi
+"$EDITOR" -- "${namebase}.sh"
+sh -e -- "${namebase}.sh"
 
-rm -r -- "$(dirname "${namebase}")"
+end # exit normaly