libreblacklist: learn `-h`

1 files changed, 41 insertions, 5 deletions

diff --git a/src/lib/libreblacklist b/src/lib/libreblacklist
index 293f3ac..6876a2b 100755
--- a/src/lib/libreblacklist
+++ b/src/lib/libreblacklist
@@ -19,7 +19,7 @@
 . $(librelib conf.sh)
 
 # Usage: blacklist-normalize <$file
-# Normalizes the syntax of the blacklist on stdin.
+# Normalizes the syntax of the blacklist on stdin
 blacklist-normalize() {
 	sed -e 's/^[^:]*$/&::/' -e 's/^[^:]*:[^:]*$/&:/'
 }
@@ -77,25 +77,61 @@ blacklist-lookup() {
 }
 
 # Usage: blacklist-cat | blacklist-get-pkg
-# Outputs only the package name field of the blacklist line(s) on stdin.
+# Prints only the package name field of the blacklist line(s) on stdin.
 blacklist-get-pkg() {
 	blacklist-normalize | cut -d: -f1
 }
 
 # Usage: blacklist-cat | blacklist-get-rep
-# Outputs only the replacement package field of the blacklist line(s) on stdin.
+# Prints only the replacement package field of the blacklist line(s) on stdin.
 blacklist-get-rep() {
 	blacklist-normalize | cut -d: -f2
 }
 
 # Usage: blacklist-cat | blacklist-get-reason
-# Outputs only the reason field of the blacklist line(s) on stdin.
+# Prints only the reason field of the blacklist line(s) on stdin.
 blacklist-get-reason() {
 	blacklist-normalize | cut -d: -f3-
 }
 
 if [[ "${0##*/}" == libreblacklist ]]; then
+	usage-outside() {
+		sed -n '/^# Usage:/,/()/p' $0 |
+		tr '\n' '\r' | sed 's/\s*()\s*[{(]/\n/g'
+	}
+	usage-inside() {
+		sed 's/\r/\n/g'<<<"$1"|sed '/^$/d'
+	}
+	usage() {
+		if [[ $# == 0 ]]; then
+			printf "Usage: %s [-h] COMMAND [ARGUMENTS]\n" "${0##*/}"
+			echo "Tool for working with the nonfree software blacklist"
+			echo
+			echo "Commands:"
+			usage-outside | while read -r sec; do sec="$(usage-inside "$sec")"
+				<<<"$sec" sed -n \
+					-e 's/blacklist-//g' \
+					-e 's/^# //' \
+					-e '2p;$p' |
+				tac|tr '\n' '\t'
+				echo
+			done|column -t -s"$(printf '\t')"|sed 's/^/  /'
+		else
+			usage-outside | while read -r sec; do sec="$(usage-inside "$sec")"
+				cmd=$(<<<"$sec" sed -n 's/.*blacklist[ -]//;$p')
+				if [[ "$cmd" == "$1" ]]; then
+					<<<"$sec" sed -n \
+						-e "s/blacklist-/${0##*/} /g" \
+						-e 's/^# //p'
+				fi
+			done
+		fi
+	}
 	_blacklist_cmd=$1
 	shift
-	"blacklist-$_blacklist_cmd" "$@"
+	if [[ $_blacklist_cmd == -h ]]; then
+		usage "$@"
+	else
+		"blacklist-$_blacklist_cmd" "$@"
+	fi
 fi