make usage an error

diff --git a/doc/special_remotes/compute/git-annex-compute-wasmedge b/doc/special_remotes/compute/git-annex-compute-wasmedge
index b93adb937072efa776a26ba15883d06dc09dacb2..51d7f3d40d892bbf89f1822d8bb954c9a0d953e5 100755 (executable)
--- a/doc/special_remotes/compute/git-annex-compute-wasmedge
+++ b/doc/special_remotes/compute/git-annex-compute-wasmedge
@@ -6,8 +6,9 @@
 set -e
 
 if [ -z "$1" ]; then
-       echo "Usage: file.wasm [inputs] -- [outputs] -- [options]"
-       echo "Example: concat.wasm foo bar -- baz --"
+       echo "Usage: file.wasm [inputs] -- [outputs] -- [options]" >&2
+       echo "Example: concat.wasm foo bar -- baz --" >&2
+       exit 1
 fi
 
 stage=1