Redirect STDOUT by variable in Bash

Question

I want to create a script which can be run both in verbose and silent mode if preferred. My idea was to create a variable which contains "&> /dev/null" and if the script is runned silently I just clear it. The silent mode works fine but if I want to pass this as the last "argument" to something (see my example down) it does not work.

Here is an example: I want to zip something (I know there is a -q option, the question is more like theorethical) and if I write this it works as I intended:

$ zip bar.zip foo
  adding: foo (stored 0%)
$ zip bar.zip foo &> /dev/null
$

But when I declare the &> /dev/null as a variable I get this:

$ var="&> /dev/null"
$ zip bar.zip foo "$var"
zip warning: name not matched: &> /dev/null
updating: foo (stored 0%)

I saw other solutions to redirect parts of the script by intention but I'm curious if my idea can work and if not, why not? It would be more convenient to use something like this in my script because I only need to redirect some lines or commands but too much to surround each with an if:

I'm trying something like this to be clear:

if verbose
verbose="&> /dev/null"
else
verbose=

command1 $1 $2
command2 $1
command3 $1 $2 $3 "$verbose"
command4

Answer 1

bash will recognize a file name of /dev/stdout as standard output, when used with a redirection, whether or not your file system has such an entry.

# If an argument is given your script, use that value
# Otherwise, use /dev/stdout
out=${1:-/dev/stdout}

zip bar.zip foo > "$out"