#121 use #!/usr/bin/env bash for portability across different *nixes

src/main/java/picocli/AutoComplete.java

@@ -96,7 +96,7 @@ private static <T> List<T> filter(List<T> list, Predicate<T> filter) {
     }
 
     private static final String HEADER = "" +
-            "#!bash\n" +
+            "#!/usr/bin/env bash\n" +
             "#\n" +
             "# %1$s Bash Completion\n" +
             "# =======================\n" +

src/test/resources/basic.bash

@@ -1,4 +1,4 @@
-#!bash
+#!/usr/bin/env bash
 #
 # basicExample Bash Completion
 # =======================

src/test/resources/nestedSubcommands.bash

@@ -1,4 +1,4 @@
-#!bash
+#!/usr/bin/env bash
 #
 # hierarchy Bash Completion
 # =======================