Require bash4 to run bootstrap

Fixes #797

(or, at least makes it fail gracefully with an advice)

Signed-off-by: Alexey Neyman <stilor@att.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/bootstrap b/bootstrap
index f5784cd..d01a7de 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1,5 +1,11 @@
 #!/bin/bash
 
+if [ "${BASH_VERSINFO[0]}" -lt 4 ]; then
+    echo "Your BASH shell version (${BASH_VERSION}) is too old." >&2
+    echo "Run bootstrap on a machine with BASH 4.x" >&2
+    exit 1
+fi
+
 ########################################
 # Common meta-language implementation. Syntax:
 #