Unify shell script style

bin/rfcopen.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-# env
+# rfcopen
 # Written in 2019 by Lucas
 # CC0 1.0 Universal/Public domain - No rights reserved
 #
@@ -10,12 +10,20 @@
 # Dedication along with this software. If not, see
 # <http://creativecommons.org/publicdomain/zero/1.0/>.
 
-usage() {
+usage()
+{
 	printf "Usage: %s [-T] rfc-number\n" "${0##*/}" >&2
 	exit 1
 }
 
-tonumber() {
+err()
+{
+	printf "%s: %s\n" "${0##*/}" "$*" >&2
+	exit 1
+}
+
+tonumber()
+{
 	printf "%u" "$1" 2>/dev/null
 }
 
@@ -32,18 +40,13 @@ while getopts T flag; do
 done
 shift $(($OPTIND - 1))
 
-if [ $# -ne 1 ] || [ -z "$1" ] || ! n=$(tonumber "$1"); then
-	usage
-fi
+[ $# -eq 1 ] && [ -n "$1" ] && n=$(tonumber "$1") || usage
 rfcfile=$RFCDIR/rfc$n.txt
 url=https://tools.ietf.org/rfc/rfc$n.txt
 
 mkdir -p "$RFCDIR"
 if [ ! -f "$rfcfile" ]; then
-	if ! $torsocks ftp -Vo "$rfcfile" "$url"; then
-		printf "%s: Couldn't fetch RFC %u\n" "${0##*/}" "$n" >&2
-		exit 1
-	fi
+	$torsocks ftp -Vo "$rfcfile" "$url" || err "Couldn't fetch RFC $n."
 fi
 
 ${PAGER:-more} "$rfcfile"