Question

Is it possible from within a bash script to check if a mysql database exists. Depending on the result then perform another action or terminate the script?

Answer 1

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 @billkarwin
RESULT=`mysqlshow --user=XXXXXX --password=XXXXXX myDatabase| grep -v Wildcard | grep -o myDatabase`
if [ "$RESULT" == "myDatabase" ]; then
    echo YES
fi

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

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

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

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

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