Add simple utility to convert from one base to another.

multibase-conv/main.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	
+	multibase "github.com/multiformats/go-multibase"
+)
+
+func main() {
+	if len(os.Args) != 3 {
+		fmt.Printf("usage: %s CID NEW-BASE\n", os.Args[0])
+		os.Exit(1)
+	}
+
+	cid := os.Args[1]
+	newBase := os.Args[2]
+
+	_, data, err := multibase.Decode(cid)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+
+	newCid, err := multibase.Encode(multibase.Encoding(newBase[0]), data)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("%s\n", newCid)
+}