MySQL password input in bash script

问题:

I have a bash script that needs to perform a couple actions in MySQL. So far I have something like this:

#!/bin/sh
read -p "Enter your MySQL username: " $sqluname
read -sp "Enter your MySQL password (ENTER for none): " $sqlpasswd
/usr/bin/mysql -u $sqluname -p $sqlpasswd << eof
*some SQL stuff*
eof

This works well until it's used with a MySQL username that has a blank password. The user hits ENTER at my password prompt, but then they receive another prompt to "Enter your password" again from MySQL.

How can I avoid this second password prompt and make the script deal with both blank and non-blank passwords?

回答1:

Check if the password is blank or not, and if it is, then omit the -p switch altogether.

read -p "Enter your MySQL username: " $sqluname
read -sp "Enter your MySQL password (ENTER for none): " $sqlpasswd
if [ -n "$sqlpasswd" ]; then
  /usr/bin/mysql -u $sqluname -p $sqlpasswd << eof
else
  /usr/bin/mysql -u $sqluname << eof
fi

Later edit to avoid a whole if-then-else block:

command="/usr/bin/mysql -u $sqluname"
[ -n "$sqlpasswd" ] && command="$command -p$sqlpasswd"
eval $command

回答2:

You'd need to specify the -n switch if $sqlpasswd is empty (instead of -p $sqlpasswd).