How to read hidden input from terminal and pipe it to another command-CodePudding

I would like to be able securely type text in terminal and pipe it to another command to:

Not be recorded in terminal history
Be hidden as you type it
Not be recorded in any file or environmental variable
Be in memory for shortest possible time

Ideally:

Using commonly installed tools on linux
Easy to use as echo
Not having to create any scripts/files
Can be piped to other commands

Example of non secure input

echo "secret" | wc -c

Almost what I want:

read -s | wc -c

Basically the same way how you input password to sudo and similar.

My use case

echo "secret" | gpg --encrypt --armor -r 1234567890ABCDEF | xclip

I am looking for a way with restrictions I mentioned in points above. Knowing that what I am looking for doesn't exist is also an answer I will accept and mark.

I created alias from accepted answer

alias secnote="{ read -s; printf %s $REPLY; } | gpg --encrypt --armor -r 123467890ABCDEF | pbcopy"

CodePudding user response：

Is this what you wanted to achieve ?

$ read -s       # I type `secret`
$ echo $REPLY
secret
$ printf %s $REPLY | wc -c
6
$ unset REPLY
$ echo $REPLY
# empty now

Or you want one-liner like this :

{ read -s -p "Input a secret: "; printf %s $REPLY; } | wc -c

If you define an alias :

alias readp='{ read -s -p "Input a secret: "; printf %s $REPLY; }'

then you can do readp | wc -c