librefetch: make the second argument optional, document

1 files changed, 31 insertions, 9 deletions

diff --git a/src/librefetch/librefetch b/src/librefetch/librefetch
index 368bfb4..3d37123 100755
--- a/src/librefetch/librefetch
+++ b/src/librefetch/librefetch
@@ -27,16 +27,30 @@ trap cleanup EXIT
 
 cmd=${0##*/}
 usage() {
-	print "Usage: %s [options] <source-url> <output-file>" "$cmd"
+	print "Usage: %s [options] <source-url> [<output-file>]" "$cmd"
 	print "Usage: %s -[g|V|h]" "$cmd"
 	print "Downloads or creates a liberated source tarball."
 	echo
+	print "The default mode is to create <output-file>, first by trying download"
+	print "mode, then create mode."
+	echo
+	print "If <output-file> isn't specified, it defaults to the non-directory"
+	print "part of <source-url>, in the current directory."
+	echo
+	print "In download mode, the glob '*://' is stripped from the beginning of"
+	print "<source-url>, and the resulting path is attempted to be downloaded"
+	print "from the configured mirror."
+	echo
+	print "In create mode, it looks at a build script, and uses that to create"
+	print "the source tarball.  <source-url> is ignored, except that it is used"
+	print "to set the default value of <output-file>."
+	echo
 	print "The default build script is 'PKGBUILD', or 'SRCBUILD' if it exists."
 	echo
 	print "Unrecognized options are passed straight to makepkg."
 	echo
 	print "Example usage:"
-	print '  $ %s libre://mypackage-1.0.tar.gz $SRCDEST/mypackage-1.0.tar.gz.part' "$cmd"
+	print '  $ %s libre://mypackage-1.0.tar.gz' "$cmd"
 	echo
 	print "Options:"
 	print " Settings:"
@@ -106,13 +120,21 @@ main() {
 
 	########################################################################
 
-	if [[ ${#extra_opts[@]} != 2 ]]; then
-		print "%s: %d non-flag arguments found, expected 2: %s" "$cmd" ${#extra_opts[@]} >> /dev/stderr
-		usage >> /dev/stderr
-		return 1
-	fi
-	local src="${extra_opts[0]#*://}"
-	local dst="$(readlink -m "${extra_opts[1]}")"
+	local src dst
+	case ${#extra_opts[@]} in
+		1)
+			src="${extra_opts[0]#*://}"
+			dst="$(readlink -m "${src##*/}")"
+			;;
+		2)
+			src="${extra_opts[0]#*://}"
+			dst="$(readlink -m "${extra_opts[1]}")"
+			;;
+		*)
+			print "%s: %d non-flag arguments found, expected 1 or 2: %s" "$cmd" ${#extra_opts[@]} >> /dev/stderr
+			usage >> /dev/stderr
+			return 1
+	esac
 
 	# Mode: download #######################################################