Direct output from fail() to stderr

This allows callers to more easily differentiate valid output from
errors.  A recent example is facter.  When calling virt-what for its
virtual fact, it gets 'virt-what: this script must be run as root' as
the fact value when run as non-root:

$ facter | grep ^virtual
virtual => virt-what: this script must be run as root

This is mildly related to RHBZ #719611¹.

¹ https://bugzilla.redhat.com/show_bug.cgi?id=719611

diff --git a/virt-what.in b/virt-what.in
index 21488e7..297956d 100644 (file)
--- a/virt-what.in
+++ b/virt-what.in
@@ -34,7 +34,7 @@ skip_qemu_kvm=false
 VERSION="@VERSION@"
 
 function fail {
-    echo "virt-what: $1"
+    echo "virt-what: $1" >&2
     exit 1
 }