more tr portability test script fixes

diff --git a/t/t7003-filter-branch.sh b/t/t7003-filter-branch.sh
index 6e14bf1c7f0991bbaab217e8a08bae0cacfe1ab1..553131fcf4cc418309e0cb750d885a5fbfe0fe47 100755 (executable)
--- a/t/t7003-filter-branch.sh
+++ b/t/t7003-filter-branch.sh
@@ -4,7 +4,7 @@ test_description='git-filter-branch'
 . ./test-lib.sh
 
 make_commit () {
-       lower=$(echo $1 | tr A-Z a-z)
+       lower=$(echo $1 | tr '[A-Z]' '[a-z]')
        echo $lower > $lower
        git add $lower
        test_tick