How do I echo stars (*) when reading password with `read`? - bash

Question

What do I need to do for code in Bash, if I want to echo *s in place of password characters (or even just hide the characters completely) when the user types something in using read?

Answer 1

As Mark Rushakoff pointed out, read -s will suppress the echoing of characters typed at the prompt. You can make use of that feature as part of this script to echo asterisks for each character typed:
#!/bin/bash
unset password
prompt="Enter Password:"
while IFS= read -p "$prompt" -r -s -n 1 char
do
if [[ $char == $'\0' ]]
then
break
fi
prompt='*'
password+="$char"
done
echo
echo "Done. Password=$password"

Answer 2

I really liked the answer that Wirone gave, but I didn't like that the backspacing would continue removing characters even back into the "Enter password: " prompt.
I also had some issues where pressing keys too rapidly would cause some of the characters to actually print on the screen... never a good thing when prompting for a password. =)
The following is my modified version of Wirone's answer which addresses these issues:
#!/bin/bash
unset PASSWORD
unset CHARCOUNT
echo -n "Enter password: "
stty -echo
CHARCOUNT=0
while IFS= read -p "$PROMPT" -r -s -n 1 CHAR
do
# Enter - accept password
if [[ $CHAR == $'\0' ]] ; then
break
fi
# Backspace
if [[ $CHAR == $'\177' ]] ; then
if [ $CHARCOUNT -gt 0 ] ; then
CHARCOUNT=$((CHARCOUNT-1))
PROMPT=$'\b \b'
PASSWORD="${PASSWORD%?}"
else
PROMPT=''
fi
else
CHARCOUNT=$((CHARCOUNT+1))
PROMPT='*'
PASSWORD+="$CHAR"
fi
done
stty echo
echo $PASSWORD

Answer 3

read -s should put it in silent mode:
-s Silent mode. If input is coming from a terminal, characters are not echoed.
See the read section in man bash.

Answer 4

I would like to add something to Dennis Williamson's solution:
#!/bin/bash
unset password
echo -n "Enter password: "
while IFS= read -p "$prompt" -r -s -n 1 char
do
# Enter - accept password
if [[ $char == $'\0' ]] ; then
break
fi
# Backspace
if [[ $char == $'\177' ]] ; then
prompt=$'\b \b'
password="${password%?}"
else
prompt='*'
password+="$char"
fi
done
In above example script handles backspace correctly.
Source

Answer 5

I don't know about stars, but stty -echo is your friend:
#!/bin/sh
read -p "Username: " uname
stty -echo
read -p "Password: " passw; echo
stty echo
Source: http://www.peterbe.com/plog/passwords-with-bash

Answer 6

If you don't care about it being interactive, you can simply do
read -s pass
echo "$pass" | sed 's/./*/g'
This will show a * for each character of the entered password after enter is pressed.

Answer 7

stty -echo
read something
stty echo
will stop user input being echoed to the screen for that read. Depending on what you are doing with prompts, you may want to add an extra echo command to generate a newline after the read.

Answer 8

I just made this Bash-specific function based on Dennis Williamson's, Wirone's and Logan VanCuren's answers:
ask() {
local 'args' 'char' 'charcount' 'prompt' 'reply' 'silent'
# Basic arguments parsing
while [[ "${1++}" ]]; do
case "${1}" in
( '--silent' | '-s' )
silent='yes'
;;
( '--' )
args+=( "${#:2}" )
break
;;
( * )
args+=( "${1}" )
;;
esac
shift || break
done
if [[ "${silent}" == 'yes' ]]; then
for prompt in "${args[#]}"; do
charcount='0'
prompt="${prompt}: "
reply=''
while IFS='' read -n '1' -p "${prompt}" -r -s 'char'; do
case "${char}" in
# Handles NULL
( $'\000' )
break
;;
# Handles BACKSPACE and DELETE
( $'\010' | $'\177' )
if (( charcount > 0 )); then
prompt=$'\b \b'
reply="${reply%?}"
(( charcount-- ))
else
prompt=''
fi
;;
( * )
prompt='*'
reply+="${char}"
(( charcount++ ))
;;
esac
done
printf '\n' >&2
printf '%s\n' "${reply}"
done
else
for prompt in "${args[#]}"; do
IFS='' read -p "${prompt}: " -r 'reply'
printf '%s\n' "${reply}"
done
fi
}
It could be used like:
$ ask Username
Username: AzureDiamond
AzureDiamond
$ ask -s Password
Password: *******
hunter2
$ ask First Second Third
First: foo
foo
Second: bar
bar
Third: baz
baz

Answer 9

#nxnev's answer didn't quite work for me, at least on macOS. I simplified it a bit, and now it's flawless:
#!/bin/bash
ask() {
charcount='0'
prompt="${1}: "
reply=''
while IFS='' read -n '1' -p "${prompt}" -r -s 'char'
do
case "${char}" in
# Handles NULL
( $'\000' )
break
;;
# Handles BACKSPACE and DELETE
( $'\010' | $'\177' )
if (( charcount > 0 )); then
prompt=$'\b \b'
reply="${reply%?}"
(( charcount-- ))
else
prompt=''
fi
;;
( * )
prompt='*'
reply+="${char}"
(( charcount++ ))
;;
esac
done
printf '\n' >&2
printf '%s\n' "${reply}"
}
pwd="$(ask Password)"
echo "Your password is $pwd"

Answer 10

#!/bin/bash
echo "------------------------------"
n=7
echo " Enter Password :"
for (( i=1;i<n;i++ ))
do
stty -echo
read -r -s -n 1 char
stty echo
echo -n "*"
pass+="$char"
done
echo " "
echo " Your password : $pass "
echo ""
echo "-------------------------------"