Correct me if I misunderstood your problem, if you want to read user input:
You can use the built-in SHELL read command.
example:
[myprompt]$ read -p "Insert text : " IN_TEXT
Insert text : user input
[myprompt]$ echo $IN_TEXT
user input
ps: if you use the read command for the password, you can use the "-s" option to hide the input coming from the terminal.
example2:
[myprompt]$ read -sp "Insert text : " IN_TEXT
Insert text : //stdin <<"user input"
[myprompt]$ echo $IN_TEXT
user input