Check if mysql database exists, perform action based on result

I give +1 to answer by @chown, but here's another alternative: If the bash script is running locally with the MySQL instance, and you know the path to the datadir, you can test:

if [ -d /var/lib/mysql/databasename ] ; then     # Do Stuff ...fi

This also assumes your shell user running the script has filesystem-level privileges to read the contents of the MySQL datadir. This is often the case, but it is not certain.

Example script (Thanks to Bill Karwin for the --user and --password comment!):

#!/bin/bash## --user=XXXXXX --password=XXXXXX *may* not be necessary if run as root or you have unsecured DBs but##   using them makes this script a lot more portable.  Thanks @billkarwinRESULT=`mysqlshow --user=XXXXXX --password=XXXXXX myDatabase| grep -v Wildcard | grep -o myDatabase`if [ "$RESULT" == "myDatabase" ]; then    echo YESfi

These are what the commands look like when run at a prompt:

[root@host ~]# mysqlshow myDatabaseWildcard: myDatabase+------------------+|    Databases     |+------------------+| myDatabase       |+------------------+

If no DB exists, the output will look like this:

[root@host ~]# mysqlshow myDatabaseWildcard: myDatabase+-----------+| Databases |+-----------++-----------+

Then, parse the output and do what you need to based on if it exists or not!

mysqlshow "test" > /dev/null 2>&1 && echo "Database exists."

Depending on the exit status of the mysqlshow command, it will execute the following echo.