connect to mysql db and execute query and export result to variable - bash script

Question

I want to connect to mysql databse and execute some queries and export its result to a varibale, and do all of these need to be done entirely by bash script

I have a snippet code but does not work.

#!/bin/bash

BASEDIR=$(dirname $0)
cd $BASEDIR

mysqlUser=n_userdb
mysqlPass=d2FVR0NA3
mysqlDb=n_datadb

result=$(mysql -u $mysqlUser -p$mysqlPass -D $mysqlDb -e "select * from confs limit 1")

echo "${result}" >> a.txt

whats the problem ?

Answer 1

The issue was resolved in the chat by using the correct password.

If you further want to get only the data , use mysql with -NB (or --skip-column-names and --batch ).

Also, the script needs to quote the variable expansions, or there will be issues with usernames/passwords containing characters that are special to the shell. Additionally, uppercase variable names are usually reserved for system variables.

#!/bin/sh

basedir=$(dirname "$0")

mysqlUser='n_userdb'
mysqlPass='d2FVR0NA3'
mysqlDb='n_datadb'

cd "$basedir" &&
mysql -NB -u "$mysqlUser" -p"$mysqlPass" -D "$mysqlDb" \
      -e 'select * from confs limit 1' >a.txt 2>a-err.txt

Ideally though, you'd use a my.cnf file to configure the username and password.

See eg

• MySQL Utilities - ~/.my.cnf option file
• mysql .my.cnf not reading credentials properly?

Answer 2

Do this:

result=$(mysql -u $mysqlUser -p$mysqlPass -D $mysqlDb -e "select * from confs limit 1" | grep '^\|' | tail -1)

The $() statement of Bash has trouble handling variables which contain multiple lines so the above hack greps only the interesting part: the data