How to compress a mysql dump using 7z via a pipe?

Question

I've been attempting to compress my mysqldump output via 7z using the pipe operator (I have seen this question, but its answer uses xz not 7z). This is what I have tried so far:

mysqldump -u root -p Linux_Wiki | 7z > backup.sql.7z

and:

mysqldump -u root -p Linux_Wiki | 7za > backup.sql.7z

and:

mysqldump -u root -p Linux_Wiki | '7za a' > backup.sql.7z

and:

mysqldump -u root -p Linux_Wiki | `7za a` > backup.sql.7z

All four failed, but I am sure I have p7zip installed, after all the last of these attempts gave this output:

Enter password: bash: 7-Zip: command not found
mysqldump: Got error: 1045: Access denied for user 'root'@'localhost' (using password: NO) when trying to connect

Solution

First store the password in a file called .my.cnf in the users home directory with the following format:

[mysqldump]
password=secret

---

Then, you have to use mysqldump without the -p flag to dump a mysql database (it now uses the password from the file):

mysqldump -u root database | 7z a -si backup.sql.7z

• The a flag of 7z adds to the archive
• -si means to read from the standard input (from the anonymous pipe).

Comments

[identify]

Sorry, rofl, I forgot the dump (I have edited my question accordingly), I did use mysqldump from the command-line though. Your code, when I substituted Linux_Wiki as my database I got the output: Enter password: 7-Zip [64] 9.38 beta Copyright (c) 1999-2014 Igor Pavlov 2015-01-03 p7zip Version 9.38.1 (locale=en_AU.UTF-8,Utf16=on,HugeFiles=on,4 CPUs,ASM) Error: backup.sql.7z is not supported archive System error: Operation not permitted mysqldump: Got error: 1045: Access denied for user 'root'@'localhost' (using password: NO) when trying to connect

[identify]

I think you missed a > after -si. But even when I added the > I got the error: Enter password: mysqldump: Got errno 32 on write

[chaos]

@BrentonHorne No, it is meant without a >. The error comes from the mysqldump command which cannot connect to the database: Access denied for user 'root'@'localhost' (using password: NO). The username or password is wrong.

[identify]

It didn't give me a chance to provide my password. It just gave me that error, before I could even enter my password.

[chaos]

@BrentonHorne See my edit

[identify]

By my 'home directory' do you mean ~/? I log in using the mysql root account, so should I store it in /root?

[chaos]

@BrentonHorne yes ~/.my.cnf. You can remove it after the operation.

[identify]

I'm afraid I'm still getting errors 7-Zip [64] 9.38 beta Copyright (c) 1999-2014 Igor Pavlov 2015-01-03 p7zip Version 9.38.1 (locale=en_AU.UTF-8,Utf16=on,HugeFiles=on,4 CPUs,ASM) Error: backup.sql.7z is not supported archive System error: Operation not permitted mysqldump: Got errno 32 on write

[chaos]

@BrentonHorne The file backup.sql.7z still persists in the directory from previous attempts and is most probably empty; remove it.