Calling an utility with wrong parameters is an error

app/bak

@@ -4,10 +4,10 @@
 # Makes incremental backups from the first parameter to the second.
 # shellcheck disable=SC1091,SC2034 # File not following, appears unused.
 readonly \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
-[ "$#" -eq 2 ] || cya Usage: bak source destination.
+[ "$#" -eq 2 ] || die bak: try bak [source directory] [destination directory]
 readonly \
 	DST="$2" \
 	SRC="$1"

app/chowner

@@ -5,12 +5,11 @@
 # and directories started from the seconds argument.
 # shellcheck disable=SC1091,SC2034 # File not following, appears unused.
 readonly \
-	BASE_APP_USAGE='Usage: chowner user directory.' \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
 beroot
-[ "$#" -eq 2 ] || cya "$BASE_APP_USAGE"
+[ "$#" -eq 2 ] || die chowner: try chowner [user directory]
 readonly \
 	DIR="$2" \
 	USR="$1"

app/flactomp3

@@ -3,10 +3,10 @@
 # Copyright 2019-2024 David Rabkin
 # shellcheck disable=SC1091,SC2034 # File not following, variable unused.
 readonly \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
-[ "$#" -eq 1 ] || cya Usage: flactomp3 filename.
+[ "$#" -eq 1 ] || die flactomp3: try flactomp3 [file name]
 readonly \
 	SRC="$1" \
 	TAG="$BASE_WIP"/tags

app/ival

@@ -4,11 +4,11 @@
 # Validates image files.
 # shellcheck disable=SC1091,SC2034 # File not following, variable unused.
 readonly \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
 validate_cmd convert
-[ "$#" -eq 1 ] || cya Usage: "$BASE_IAM" directory.
+[ "$#" -eq 1 ] || cya ival: try ival [user directory]
 readonly DIR="$1"
 isreadable "$DIR" || die Directory "$DIR" is not readable.
 find "$DIR" -type f \

app/pingo

@@ -5,11 +5,8 @@
 # shellcheck disable=SC1091,SC2034 # File not following, appears unused.
 set -- "$@" --quiet
 readonly \
-	BASE_APP_VERSION=0.9.20240222 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
-[ $# -ge 1 ] || {
-	printf 'Usage: pingo [network resource].\n'
-	cya
-}
+[ $# -ge 1 ] || die pingo: try pingo [network resource]
 { ping "$1" 2>&1 1>&3 3>&- | tologe; } 3>&1 1>&2 | totsout

app/scanner

@@ -4,7 +4,7 @@
 # Detects if a device with a certain MAC address is in the local network.
 # shellcheck disable=SC1091,SC2034 # File not following, variable unused.
 readonly \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20231212
 . base.sh
 MAXV=10
@@ -55,7 +55,7 @@ wait() {
 # Starting point.
 beroot
 validate_cmd arp-scan
-[ "$#" -eq 1 ] || cya "Usage: $BASE_IAM [MAC-ADDRESS:list]"
+[ "$#" -eq 1 ] || die scanner: try scanner [mac address:list]
 [ "$1" = list ] && {
 	$SCAN
 	cya

app/tex

@@ -3,7 +3,7 @@
 # Copyright 2020-2024 David Rabkin
 # shellcheck disable=SC1091 # File not following.
 . base.sh
-[ "$#" -eq 1 ] || cya Usage: "$BASE_IAM" FILENAME.tex
+[ "$#" -eq 1 ] || die tex: try tex [file name]
 [ -r "$1" ] || die Unable to read from source "$1".
 validate_cmd tex dvipdfm
 NME=$(basename -- "$1")

app/tru

@@ -10,7 +10,7 @@
 # shellcheck disable=SC3043 # Uses local variables.
 # shellcheck disable=SC1091,SC2034 # File not following, appears unused.
 readonly \
-	BASE_APP_VERSION=0.9.20240208 \
+	BASE_APP_VERSION=0.9.20240806 \
 	BASE_MIN_VERSION=0.9.20240104
 . base.sh
 
@@ -62,7 +62,7 @@ tid() {
 
 validation() {
 	validate_cmd awk nc tr transmission-remote transmission-show
-	[ "$#" -eq 3 ] || cya Usage: tru host:port user:pass torrent-file.
+	[ "$#" -eq 3 ] || die tru: try tru [host:port user:pass torrent-file]
 
 	# Single ':' means there is no authentication data.
 	[ "$2" != : ] && AUT="--auth $2" || AUT=''