Bash – How to add a password to a BASH script

bashpasswordscripting

I want to create a script to run the following BASH command:

mysqldump -u [username] -p [db_name] > [path to backup file]

Which results in a backup file. When running this in BASH, it prompts for a password before continuing.

How do I craft this in a BASH script so that the password is automatically entered?

Can this be done securely?

Best Answer

The best kind of approach here is to do something like:

mysqldump --defaults-extra-file=/path/to/auth.cnf ...

Where auth.cnf looks like:

[client]
user=the-user
password=the-password

Then make sure the file is only readable by whomever is meant to run that script. The script itself can be world readable.

Related Solutions

Bash – Why Doesn’t My Script Recognize Aliases?

First of all, as ddeimeke said, aliases by default are not expanded in non-interactive shells.

Second, .bashrc is not read by non-interactive shells unless you set the BASH_ENV environment variable.

But most importantly: don't do that! Please? One day you will move that script somewhere where the necessary aliases are not set and it will break again.

Instead set and use variables as shortcuts in your script:

#!/bin/bash

CMDA=/path/to/gizmo
CMDB=/path/to/huzzah.sh

for file in "$@"
do
    $CMDA "$file"
    $CMDB "$file"
done

Pipe Password to Application When Asked in Bash

Use empty:

With the password safely stored (it's a way of saying...)

$ echo password > pwd-file

Start process with empty. (You would omit -L log in the real case.)

$ empty -f -i fifo1 -o fifo2 -L log curl -u user http://example.com

Send the contents of pwd-file to empty's input pipe, which the process sees as both its stdin and /dev/tty.

$ empty -s -c -o fifo1 < pwd-file

This is what happened in the pseudo terminal:

$ cat log
<<<Enter host password for user 'user':>>>password
<<<

Best Answer

Related Solutions

Bash – Why Doesn’t My Script Recognize Aliases?

Pipe Password to Application When Asked in Bash

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