How to run script commands from variables?

Question

I tried to run commands using pipes.

Basic:

single=\"ls -l\"
$single

which works as expected

Pipes

Answer 1

You need a heredoc to do this correctly. In answer to POSIX compliant way to see if a function is defined in an sh script, I detailed how to read a script into a variable, programmatically parse it for information and/or modify it as necessary, then execute it from another script or shell function. That's basically what you're trying to do, and the heredoc makes it possible because it provides a file descriptor:

% multi='ls -l | grep e'
% sh <<_EOF_
> ${multi}
> _EOF_
< desired output >

That would solve your simple example case. See my other answer for more.

-Mike