Add missing format arg.

CHANGELOG

@@ -1,3 +1,7 @@
+Release 1.2.1 - 2018-09-15
+
++ Add missing format argument to Errorf call in kgz.
+
 Release 1.2.0 - 2018-09-15
 
 + Adds the kgz command line utility.

README.md

@@ -3,6 +3,9 @@ GOUTILS
 This is a collection of small utility code I've written in Go; the `cmd/`
 directory has a number of command-line utilities. Rather than keep all
 of these in superfluous repositories of their own, I'm putting them here.
+Note that for packaging purposes, the goutils-pkg repo should be used: it
+pins the library versions to working copies and vendors all depdencies. See
+https://github.com/kisom/goutils-pkg for more details.
 
 Contents:
 

cmd/kgz/main.go

@@ -113,7 +113,7 @@ func pathForUncompressing(source, dest string) (string, error) {
 
 	source = filepath.Base(source)
 	if !strings.HasSuffix(source, gzipExt) {
-		return "", errors.Errorf("%s is a not gzip-compressed file")
+		return "", errors.Errorf("%s is a not gzip-compressed file", source)
 	}
 	outFile := source[:len(source)-len(gzipExt)]
 	outFile = filepath.Join(dest, outFile)
@@ -127,7 +127,7 @@ func pathForCompressing(source, dest string) (string, error) {
 
 	source = filepath.Base(source)
 	if strings.HasSuffix(source, gzipExt) {
-		return "", errors.Errorf("%s is a gzip-compressed file")
+		return "", errors.Errorf("%s is a gzip-compressed file", source)
 	}
 
 	dest = filepath.Join(dest, source+gzipExt)