Command substitution problem with bash, sqlite3

[donsy]

Scipt:

#!/bin/bash

cmd='sqlite3 test.db "select col1, col2 from table1;"'

result=$($cmd) # doesn't work

#result=$(sqlite3 test.db "select col1, col2 from table1;") # this works when uncommented

echo $result

When executed gives the following error:

sqlite3: Error: too many options: "col1,"
Use -help for a list of options.

However if I uncomment line 4 it works fine.

[schragge]

See this post and this answer. What you get after $cmd gets expanded to its value is equivalent of

result=$(sqlite3 test.db \"select col1, col2 from table1;\")

In bash, you should use an array for this to work as intended:

#!/bin/bash

cmd=(sqlite3 test.db 'select col1, col2 from table1;')
result=$("${cmd[@]}")

or use zsh instead of bash.

[sisco311]

Why do you want to store the command in a variable? If you have to invoke it multiple times, then use a function.

[donsy]

See this post and this answer. What you get after $cmd gets expanded to its value is equivalent of

result=$(sqlite3 test.db \"select col1, col2 from table1;\")

In bash, you should use an array for this to work as intended:

#!/bin/bash

cmd=(sqlite3 test.db 'select col1, col2 from table1;')
result=$("${cmd[@]}")

or use zsh instead of bash.

@schragge: Thank you. It works.

@sisco311: That script was for illustrative purposes only, line 4 was commented.

[sisco311]

@schragge: Thank you. It works.

@sisco311: That script was for illustrative purposes only, line 4 was commented.

I know. That's why I asked why do you want to store the sqlite3 command and its parameters in a variable. This seems like a strange problem to want to solve.

[donsy]

I know. That's why I asked why do you want to store the sqlite3 command and its parameters in a variable. This seems like a strange problem to want to solve.

I'm always open to suggestion. How would you do it?

[sisco311]

I'm always open to suggestion. How would you do it?

Do what?