How to execute a bash command stored as a string with quotes and asterisk

bash scripting escaping quotes
Barth picture Barth · Jan 5, 2010 · Viewed 288.2k times · Source

I try to execute the following command :

mysql AMORE -u username -ppassword -h localhost -e "SELECT  host  FROM amoreconfig"

I store it in a string :

cmd="mysql AMORE -u username -ppassword -h localhost -e\"SELECT  host  FROM amoreconfig\""

Test it : 

echo $cmd
mysql AMORE -u username -ppassword -h localhost -e"SELECT host FROM amoreconfig"

Try to execute by doing : 

$cmd

And I get the help page of mysql :

mysql  Ver 14.14 Distrib 5.1.31, for pc-linux-gnu (i686) using readline 5.1
Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL license
Usage: mysql [OPTIONS] [database]
(...)

I guess I am doing something plain wrong with the quotes but can't find out what is the problem.

Answer

slebetman picture slebetman · Jan 5, 2010

Have you tried:

eval $cmd

For the follow-on question of how to escape * since it has special meaning when it's naked or in double quoted strings: use single quotes.

MYSQL='mysql AMORE -u username -ppassword -h localhost -e'
QUERY="SELECT "'*'" FROM amoreconfig" ;# <-- "double"'single'"double"
eval $MYSQL "'$QUERY'"

Bonus: It also reads nice: eval mysql query ;-)

Related questions

How do I tell if a regular file does not exist in Bash?

I've used the following script to see if a file exists: #!/bin/bash FILE=$1 if [ -f $FILE ]; then echo "File $FILE exists." else echo "File $FILE does not exist." fi What's the correct syntax to use if I only want …

Read More
How do I split a string on a delimiter in Bash?

I have this string stored in a variable: IN="[email protected];[email protected]" Now I would like to split the strings by ; delimiter so that I have: ADDR1="[email protected]" ADDR2="[email protected]" I don't necessarily …

Read More
How do I parse command line arguments in Bash?

Say, I have a script that gets called with this line: ./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile or this one: ./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile What's the accepted way of parsing this such …

Read More