Use a compatible to lowercase syntax for bash < 4 (#41)

1 files changed, 1 insertions, 1 deletions

diff --git a/otp.bash b/otp.bash
index 6a28fbd..16d0ef4 100755
--- a/otp.bash
+++ b/otp.bash
@@ -317,7 +317,7 @@ cmd_otp_code() {
   case "$otp_type" in
     totp)
       cmd="$OATH -b --totp"
-      [[ -n "$otp_algorithm" ]] && cmd+="=${otp_algorithm,,}"
+      [[ -n "$otp_algorithm" ]] && cmd+=$(echo "=${otp_algorithm}"|tr "[:upper:]" "[:lower:]")
       [[ -n "$otp_period" ]] && cmd+=" --time-step-size=$otp_period"s
       [[ -n "$otp_digits" ]] && cmd+=" --digits=$otp_digits"
       cmd+=" $otp_secret"