Fix all ShellCheck warnings

IOW, `make check-shellcheck` passes.

12 files changed, 50 insertions, 18 deletions

diff --git a/bin/backup b/bin/backup
index 0ebef43..be7d996 100755
--- a/bin/backup
+++ b/bin/backup
@@ -93,6 +93,8 @@ ARCHIVE_TAG="${1:-manual}"
 
 run() {
 	set -x
+	# The contents of $VERBOSE_FLAGS doesn't involve user input:
+	# shellcheck disable=2086
 	borg create \
 		$VERBOSE_FLAGS                    \
 		--comment "$COMMENT"              \
diff --git a/bin/bins b/bin/bins
index 28e92f1..710cf8a 100755
--- a/bin/bins
+++ b/bin/bins
@@ -64,8 +64,10 @@ shift $((OPTIND- 1))
 F="$XDG_CACHE_HOME/euandreh/bins"
 
 IFS=:
+# Word-splitting is the goal:
+# shellcheck disable=2086
 if stest -rdq -n "$F" $PATH; then
-	trap "rm -f $F-tmp" EXIT
+	trap 'rm -f $F-tmp' EXIT
 	stest -lxf $PATH | sort -u > "$F"-tmp
 	mv "$F"-tmp "$F"
 fi
diff --git a/bin/boop b/bin/boop
index d2de30f..a7792b3 100755
--- a/bin/boop
+++ b/bin/boop
@@ -77,7 +77,7 @@ else
 	N=1
 fi
 
-CMD="$@"
+CMD="$*"
 msg -"$N" -bs -D "${MESSAGE:-$CMD}"
 
 exit "$STATUS"
diff --git a/bin/cl b/bin/cl
index 77f6fb6..a38d00a 100755
--- a/bin/cl
+++ b/bin/cl
@@ -187,6 +187,7 @@ for f in "$@"; do
 	INTERACTIVE=false
 	escape_name "$f" >> "$SCRIPT"
 done
+set --
 
 MAIN="$(mkstemp)"
 if [ "$NO_RC" = false ] && [ -e "$LISP_CLI_RC" ]; then
@@ -217,7 +218,7 @@ if [ -z "$IMPL" ]; then
 		fi
 	done
 	if [ -z "$IMPL" ]; then
-		printf 'Could not find any implementation in $PATH.\n' >&2
+		printf "Could not find any implementation in \$PATH.\n" >&2
 		exit 2
 	fi
 fi
@@ -228,6 +229,7 @@ if [ "$SKIP_DEFAULT_IMAGE" = false ] && [ -z "$IMAGE" ] &&
 	IMAGE="$DEFAULT_IMAGE"
 fi
 
+
 case "$IMPL" in
 	abcl)
 		exit 4
@@ -242,19 +244,19 @@ case "$IMPL" in
 		exit 4
 		;;
 	clisp)
-		ARGS="-ansi -i $MAIN"
+		set -- -ansi -i "$MAIN"
 		if [ -n "$IMAGE" ]; then
-			set -- -M "$IMAGE"
+			set -- "$@" -M "$IMAGE"
 		fi
 		if [ "$NO_RC" = true ]; then
-			ARGS="$ARGS -norc"
+			set -- "$@" -norc
 		fi
 		if [ "$VERBOSE" = false ]; then
-			ARGS="$ARGS -q -q"
+			set -- "$@" -q -q
 		else
 			set -x
 		fi
-		exec clisp $ARGS "$@"
+		exec clisp "$@"
 		;;
 	cmucl)
 		exit 4
@@ -269,19 +271,21 @@ case "$IMPL" in
 		exit 4
 		;;
 	sbcl)
-		ARGS="--load $MAIN"
+		set -- --load "$MAIN"
 		if [ -n "$IMAGE" ]; then
-			set -- --core "$IMAGE"
+			# The '--core' "C runtime option" must appear before the
+			# other "Lisp options", such as '--load'.
+			set -- --core "$IMAGE" "$@"
 		fi
 		if [ "$NO_RC" = true ]; then
-			ARGS="$ARGS --no-sysinit --no-userinit"
+			set -- "$@" --no-sysinit --no-userinit
 		fi
 		if [ "$VERBOSE" = false ]; then
-			ARGS="--noinform $ARGS"
+			set -- "$@" --noinform
 		else
 			set -x
 		fi
-		exec sbcl "$@" $ARGS
+		exec sbcl "$@"
 		;;
 	*)
 		printf 'Unsupported implementation: "%s".\n\n' "$IMPL" >&2
diff --git a/bin/color b/bin/color
index 05ef95b..dc610e9 100755
--- a/bin/color
+++ b/bin/color
@@ -1,4 +1,5 @@
 #!/bin/sh
+# shellcheck disable=2059
 set -eu
 
 usage() {
diff --git a/bin/dice b/bin/dice
index 93556a5..4a145d0 100755
--- a/bin/dice
+++ b/bin/dice
@@ -18,15 +18,21 @@ help() {
 		  SIZE          the size of the dice (default: 6)
 
 
+		Roll a dice of SIZE.  Caveat: rolling a dice more than once in
+		the same second will give you the same number.
+
+
 		Examples:
 
 		  Roll a dice of size 6:
 
 		    $ dice
+		    3
 
 		  Roll a D20:
 
 		    $ dice 20
+		    15
 	EOF
 }
 
@@ -63,4 +69,5 @@ shift $((OPTIND - 1))
 
 
 SIZE="${1:-6}"
-echo $(((RANDOM % SIZE) + 1))
+RAND="$(awk 'BEGIN { srand(); print int(rand()*32768) }' /dev/null)"
+echo $(((RAND % SIZE) + 1))
diff --git a/bin/grun b/bin/grun
index 982420a..74d8819 100755
--- a/bin/grun
+++ b/bin/grun
@@ -91,4 +91,6 @@ else
 	OUT="$(gpg -dq "$FILENAME" | "$@")"
 fi
 
+# GPG recipients can't contain spaces:
+# shellcheck disable=2086
 echo "$OUT" | gpg -e ${RECIPIENTS_FLAG:--r eu@euandre.org} | sponge "$FILENAME"
diff --git a/bin/httpno b/bin/httpno
index 0e8d66f..e64b872 100755
--- a/bin/httpno
+++ b/bin/httpno
@@ -45,7 +45,8 @@ help() {
 }
 
 DATA() {
-	awk 'd == 1 { print; next } /^__DATA__$/ { d = 1 }' "$0"
+	awk 'd == 1 { print; next } /^__DATA__$/ { d = 1 }' "$0" |
+		head -n -1  # trim ShellCheck quote
 }
 
 
@@ -88,6 +89,10 @@ fi
 
 
 exit
+
+# Make ShellCheck happy.  See https://github.com/koalaman/shellcheck/issues/1201
+# shellcheck disable=1112
+echo "
 __DATA__
 100 Continue
 101 Switching Protocols
@@ -148,3 +153,4 @@ __DATA__
 509 Bandwidth Limit Exceeded
 510 Not Extended
 511 Network Authentication Required
+"
diff --git a/bin/lines b/bin/lines
index b2558b8..2f0bf46 100755
--- a/bin/lines
+++ b/bin/lines
@@ -73,7 +73,7 @@ START="${1:-}"
 if [ -z "${2:-}" ]; then
 	END=1
 else
-	END=$(($2 - $START + 1))
+	END=$(($2 - START + 1))
 fi
 
 eval "$(assert-arg "$START" 'START')"
diff --git a/bin/menu b/bin/menu
index 9f1fe09..94e124f 100755
--- a/bin/menu
+++ b/bin/menu
@@ -76,7 +76,8 @@ eval "$(assert-arg "$ACTION" 'ACTION')"
 
 
 DATA() {
-	awk 'd == 1 { print; next } /^__DATA__$/ { d = 1 }' "$0"
+	awk 'd == 1 { print; next } /^__DATA__$/ { d = 1 }' "$0" |
+		head -n -1  # trim ShellCheck quote
 }
 
 show() {
@@ -144,6 +145,10 @@ esac
 
 
 exit
+
+# Make ShellCheck happy.  See https://github.com/koalaman/shellcheck/issues/1201
+# shellcheck disable=1112
+echo '
 __DATA__
 grinning face                                   😀
 smiling face with open mouth                    😃
@@ -1577,3 +1582,4 @@ Western Sahara                                 🇪🇭
 Yemen                                          🇾🇪
 Zambia                                         🇿🇲
 Zimbabwe                                       🇿🇼
+'
diff --git a/bin/msg b/bin/msg
index f685ffb..b2a6794 100755
--- a/bin/msg
+++ b/bin/msg
@@ -68,7 +68,6 @@ MAIL=false
 DESKTOP=false
 BELL=false
 ACTION_DONE=false
-SHOW_USAGE=false
 while getopts '01XsSmDbh' flag; do
 	case "$flag" in
 		0)
diff --git a/bin/yt b/bin/yt
index ddcc02d..d0ff37e 100755
--- a/bin/yt
+++ b/bin/yt
@@ -100,6 +100,9 @@ if [ -z "${FORCE:-}" ]; then
 	EXTRA_OPTIONS="--download-archive $HOME/Downloads/yt-dl/seen.txt"
 fi
 
+# The value of $EXTRA_OPTIONS doesn't depend on user input, and can't contain
+# spaces, unless $HOME contains spaces:
+# shellcheck disable=2086
 youtube-dl \
 	--batch-file "$F"                \
 	--format best                    \