I'm trying to read user input char by char, silently, as follows:

while [ 1 ]; do
  read -s -N 1

While this loop works perfectly using VNC (xterm), it works only partially using putty (xterm) or a Linux terminal, and most of other text terminals.

The problem is encountered when I become "wild" with the keyboard and striking multiple keys at the same time, and than some of the keys are echoed despite of the -s mode.

I've also tried to redirect output and stty -echo. while the first did not make any difference, the latter would be somehow helpful, minimizing the "echo"s to be less frequent, but not perfect.

Any Ideas?

  • Shouldn't that n in the read -s -N 1 command be lower case?
    – user78605
    Dec 3, 2014 at 11:00

1 Answer 1


read -s disables the terminal echo only for the duration of that read command. So if you type something in between two read commands, the terminal driver will echo it back.

You should disable echo and then call read in your loop without -s:

if [ -t 0 ]; then
  saved=$(stty -g)
  stty -echo
while read -rN1; do
if [ -t 0 ]; then
  stty "$saved"

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .