How to run bash command during redirect << EOF

Question

I know there's some way to run bash command during redirect, but I don't know how exactly it is done.

I want to do something like this:

#!/bin/bash
mysql -uUser -pPasswd << EOF
echo 'I wanna echo something by using echo which is run by bash'
use Mydb
some sql commands here
commit;
EOF

I had ever done that by mistake by using " in the "<< EOF" , but failed to make it now.

It seems more likely that you are missing some `;` in your MySQL command. — merlin2011, Jun 29 '14 at 04:50
@merlin2011 since quotes might be confusing, I'll use system command, it's so clear. Sorry for missing the ';' , I just post too hurry. — Blangero, Jun 29 '14 at 05:32
@ruakh sorry for my bad English. I want to run echo(bash) command besides(is this the correct word) a lot of mysql commands, to show the process of mysql commands. — Blangero, Jun 29 '14 at 05:34

score 6 · Accepted Answer · answered Jun 29 '14 at 04:51

6

You can use system command from within the mysql command line client:

#!/bin/bash
mysql -uUser -pPasswd << EOF
system echo 'I wanna echo something by using echo which is run by bash';
use Mydb
some sql commands here
commit;
EOF

answered Jun 29 '14 at 04:51

anubhava

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@Blangero: Is `system` command not working for you for some reason? – anubhava Jun 30 '14 at 04:06
No, it works fine, why did you ask? Did I do something wrong or confusing? @anubhava – Blangero Jun 30 '14 at 05:41
No worries I was just checking if I found some glitch with this command. – anubhava Jun 30 '14 at 06:52

score 1 · Answer 2 · answered Jun 29 '14 at 06:51

In addition to using a heredoc to interact with MySQL from bash, you can simply call mysql itself in batch mode. This is useful when you have reasonably short queries and will eliminate needing to call system from within the heredoc body. The general form in bash is:

$(mysql -uuser -hhost database.table -Bse "any valid mysql command")

(you may omit .table if it is identified in your query) To handle the information returned by mysql, it is usually advisable to return the information to an array:

results=( $(mysql -uuser -hhost database.table -Bse "any valid mysql command") )

In that regard, you can structure your scripts in a more flexible manner.

It is very useful and I'll try it next time. Thank you very much! — Blangero, Jun 30 '14 at 07:44

How to run bash command during redirect << EOF

2 Answers2

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