*: Move die() into .local/bin/helpers.sh

The function `die` was redundantly implemented in various files.

Move the function into .local/bin/helpers.sh and source that where
previously implemented.

Also prepend the program's name to the message and always terminate the
message with a newline. The newline was previously needed for a small
but unnecessary hack that prevented the need of the `[ -z "$1" ]` test.

.local/bin/filterHistory

@@ -8,14 +8,12 @@
 ##   format of zshs extended history.
 ## An automatic backup is created before deleting that can be used for recovery.
 
-die() {
-	printf "$1" >&2
-	exit ${2:-1}
-}
+# Source die()
+. "$HOME"/.local/bin/helpers.sh
 
-[[ $# -eq 1 ]] || die "Specify a history file.\n"
-[[ -e "$1" ]] || die "File does not exist.\n"
-[[ "$(stat -c '%a' "$1")" = "600" ]] || die "File permissions are off.\n"
+[[ $# -eq 1 ]] || die "Specify a history file."
+[[ -e "$1" ]] || die "File does not exist."
+[[ "$(stat -c '%a' "$1")" = "600" ]] || die "File permissions are off."
 
 # Take a history file per stdin and sort the commands per number of occurrences
 hist-sort() {

.local/bin/helpers.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+#
+# A collection of useful shell functions. This file should be sourced, rather
+# than executed.
+
+
+# Print error message, prepended by the programs name, and then exit
+#
+# Usage: die [<MESSAGE>] [<EXIT_CODE>]
+die() {
+	[ -z "$1" ] || >&2 printf "%s: %s\n" "$0" "$1"
+	exit ${2:-1}
+}

meta/git-remote

@@ -1,18 +1,16 @@
 #!/bin/sh
 
-die() {
-	printf "$1" >&2
-	exit ${2:-1}
-}
+# Source die()
+. "$HOME"/.local/bin/helpers.sh
 
 remote="$(git remote -v | grep -m1 "druckdev/dotfiles" | cut -f1)"
 : "${remote:=origin}"
 url="$(git remote get-url "$remote")"
-! printf "$url" | grep -q '^git@' || die "Using ssh already.\n" 0
+! printf "$url" | grep -q '^git@' || die "Using ssh already." 0
 
 host="$(printf "$url" | cut -d/ -f3)"
-grep -q "$host" "$HOME"/.ssh/known_hosts || die "No ssh key for $host found.\n"
+grep -q "$host" "$HOME"/.ssh/known_hosts || die "No ssh key for $host found."
 
 ssh_url="$(printf "$url" | sed 's_^https\?://_git@_;s_/_:_')"
 git remote set-url "$remote" "$ssh_url"
-die "Set $remote remote url to $ssh_url\n" $?
+die "Set $remote remote url to $ssh_url" $?

meta/git/hooks/commit-msg

@@ -9,10 +9,8 @@
 #
 # To enable this hook, save this file in ".git/hooks/commit-msg".
 
-die() {
-	printf "$1" >&2
-	exit ${2:-1}
-}
+# Source die()
+. "$HOME"/.local/bin/helpers.sh
 
 subject="$(head -1 "$1")"
 # Ignore "fixup! " and "squash! " prefix' added by `git-commit`
@@ -39,7 +37,7 @@ body="$(
 	          /^[^${git_comment_char/auto/\#}]/p"
 )"
 
-[[ ${#subject} -le 50 ]] || die "Subject too long. (<= 50)\n"
+[[ ${#subject} -le 50 ]] || die "Subject too long. (<= 50)"
 
 # The subject line has to match "${pats[@]}", but to be more verbose different
 # error messages are printed for the different 'levels' of the pattern.
@@ -54,7 +52,7 @@ msg=(
 	"Start subject with a capital letter.\n"
 	"Remove punctuation mark from end.\n"
 )
-[[ ${#msg[@]} -ge ${#pats[@]} ]] || die "Something went wrong internally.\n"
+[[ ${#msg[@]} -ge ${#pats[@]} ]] || die "Something went wrong internally."
 for ((i = 0; i < ${#pats[@]}; i++)); do
 	if ! grep -qE "$(printf "%s" "${pats[@]:0:$i+1}")" <<<"$subject"; then
 		die "${msg[$i]}"
@@ -65,6 +63,6 @@ BKP_IFS="$IFS"
 IFS='
 '
 for line in $body; do
-	[[ ${#line} -le 72 ]] || die "Body lines too long. (<= 72)\n"
+	[[ ${#line} -le 72 ]] || die "Body lines too long. (<= 72)"
 done
 IFS="$BKP_IFS"

meta/git/hooks/pre-commit

@@ -6,10 +6,8 @@
 #
 # To enable this hook, save this file in ".git/hooks/pre-commit".
 
-die() {
-	printf "$1" >&2
-	exit ${2:-1}
-}
+# Source die()
+. "$HOME"/.local/bin/helpers.sh
 
 if git rev-parse --verify HEAD >/dev/null 2>&1; then
 	against=HEAD
@@ -35,8 +33,7 @@ if [ "$allownonascii" != "true" ]; then
 		| wc -c
 	)
 	if [ $num_nonascii != 0 ]; then
-		printf "Rename files to only include ASCII characters.\n" >&2
-		die "Or set hooks.allownonascii to true.\n"
+		die "Rename files with ASCII characters only, or enable hooks.allownonascii"
 	fi
 fi