add check for bash shell

diff --git a/err b/err
index 2755e2491183ece394194c8eb3363fd9e0e539e6..a5d37524b58204af2203b735c18ca2678e327f66 100644 (file)
--- a/err
+++ b/err
@@ -36,6 +36,8 @@
 # outside of the subshell. Note, errexit + inherit_errexit doesn't have
 # any smarts around this either.
 
+if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
+
 #######################################
 # err-catch: Setup trap on ERR to print stack trace and exit (or return
 # if the shell is interactive). This is the most common use case so we