How can I use a pipe operator in a variable: OPTION="| command"?

Shell Programming and Scripting
1

I have a string of commands I am piping some data through and I want to allow command line switches to select which commands are used. I want to do something like this:

OPTION="| command3"
command1 -a -b c.txt | command2 -d -e $OPTION >result.txt

I want to do it that way because OPTION may be blank, or may be multiple commands. But it doesn't work.

Is there any way I can make it work?

2

you can use eval

OPTION="| command3"
FINALCOMMAND="command1 -a -b c.txt | command2 -d -e $OPTION"

eval $FINALCOMMAND >result.txt