read command is not taking input from the terminal

Question

I dont know if it is weird that read is not taking the input from the terminal.

The configure script, which is used in source code making process, should ask the user to give the input to select the type of Database either MYSQL or ORACLE(below is the code).

MYSQLLIBPATH="/usr/lib/mysql"
echo "Enter DataBase-Type 1-ORACLE, 2-MySQL (default MySQL):"
read in
echo $? >> /tmp/error.log
if test -z "$in" -o "$in" = "2"
then
        DATABASE=-DDB_MYSQL
         if true; then 
  MYSQL_TRUE=
  MYSQL_FALSE='#'
else
  MYSQL_TRUE='#'
  MYSQL_FALSE=
fi

        echo "Enter Mysql Library Path: (eg: $MYSQLLIBPATH (default))"
        read in
        echo $? >> /tmp/error.log
        if test -n "$in"
        then 
                MYSQLLIBPATH=`echo $in`
        fi
        echo "Mysql Lib path is $MYSQLLIBPATH"
else
         if false; then
  MYSQL_TRUE=
  MYSQL_FALSE='#'
else
  MYSQL_TRUE='#'
  MYSQL_FALSE=
fi

        DATABASE=-DDB_ORACLE
        LD_PATH=
fi

But, the read command is not asking for the user input. Its failing to take the input from the stdin.

When I checked the status of the command in the error.log it was showing
1
1

Could anyone tell why read is failing to take the input from the stdin. Are there any builtin variable which can block read taking the input?

Answer 1

Most likely read executes with standard input redirected from a file that has reached EOF. If the above is not the whole of your configure code, check that there are no input redirections. Could the code above be a part of a function which was invoked with some input from a pipe or a file? Otherwise check how configure is executed - are there any redirections?

Otherwise, the universal advice applies: try simplifying and stripping down your code until it is obvious what's happening.

BTW, it is not a good idea to make configure interactive, if you want to have your program packaged for a distribution - it's not easy to control execution of interactive programs. Consider adding support for supplying parameters through command line options.